Technology posts

The Toptal Engineering Blog is a platform for sharing projects and discussing technologies.
Ivan Cesar
An Elasticsearch Tutorial for .NET Developers

Elasticsearch is one of the most powerful full-text search engine solutions out there. Using the NEST package, you can easily leverage the power of Elasticsearch in your .NET projects.

In this article, Toptal Freelance Software Engineer Ivan Cesar shows how Elasticsearch can solve real-world full-text search problems in your .NET projects.

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Alexander Gedevanishvili
Android and iOS UI Testing with Calabash

Do you think testing your iOS or Android apps manually is faster than writing automated tests for them? Calabash, the cross-platform acceptance framework, busts that myth once and for all.

In this article, Toptal Freelance Software Engineer Alexander Gedevanishvili shows how Calabash, with its support for Cucumber, makes writing automated UI tests as simple as writing instructions in plain English.

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Konrad Gadzinowski
Creating Truly Modular Code with No Dependencies

Complex, tightly-coupled, and fragile interdependent code. We’ve all written it. The kind of code where fixing one bug creates seven more. Have you ever wondered how to create independent modular code?

In this article, Toptal Freelance Software Engineer Konrad Gadzinowski walks us through the different types of architectural paradigms you can adhere to and how to write modular and decoupled code where changes to one module have minimal impact on the overall application.

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Vignes Aruljothi
Implementing Serverless Node.js Functions Using Google Cloud

Serverless computing is an architecture style in which the code is executed in a cloud platform where we don’t need to worry about the hardware and software setup, security, performance, and CPU idle time costs. It’s an advancement of cloud computing that goes beyond infrastructure that abstracts the software environment as well. It means no configuration is required to run the code.

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Roman Vashchegin
Conquer String Search with the Aho-Corasick Algorithm

The Aho-Corasick algorithm can be used to efficiently search for multiple patterns in a large blob of text, making it a really useful algorithm in data science and many other areas.

In this article, Toptal Freelance Software Engineer Roman Vashchegin shows how the Aho-Corasick algorithm uses a trie data structure to efficiently match a dictionary of words against any text.

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Rustem Kamun
Orchestrating a Background Job Workflow in Celery for Python

In this article, I will try to give you a good understanding of which scenarios could be covered by Celery. Not only will you see interesting examples, but will also learn how to apply Celery with real world tasks such as background mailing, report generation, logging and error reporting. I will share my own way of testing tasks beyond emulation and explain a few tricks that go beyond the official documentation and took me hours of research to discover myself.

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Gabriel Livan
The 12 Worst Mistakes Advanced WordPress Developers Make

WordPress is a very popular way to get a site up and running quickly. However, in their haste, plenty of developers end up making horrible decisions. Some mistakes, like leaving WP_DEBUG set to “true,” may be easy to make. Others, like lumping all your JavaScript into a single file, are as common as lazy engineers. Whichever mistake you manage to make, read on to find out the 12 most common WordPress mistakes that new and seasoned developers make.

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Simon Boissonneault-Robert
Ngrx and Angular 2 Tutorial: Building a Reactive Application

Building a reactive web application is a lot more about how you handle events and data flow in your applications than the tools you use to do so. However, Angular 2 with Ngrx seems to be the perfect combination for building reactive applications for many reasons.

In this article, Toptal Freelance Software Engineer Simon Boissonneault-Robert walks you through a reactive web application tutorial using Angular and Ngrx and shows how these two technologies make it easy to do that.

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Dusan Simonovic
Get Started With Microservices: A Dropwizard Tutorial

Dropwizard allows developers to quickly bootstrap their projects and package applications as easily deployable standalone services. It also happens to be relatively simple to use and implement.

In this tutorial, Toptal Freelance Software Engineer Dusan Simonovic will introduce you to Dropwizard and demonstrate how you can use this powerful framework to create RESTful web services with ease.

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Luke Sapan
Ramping up Software Deployment - A Docker Swarm Tutorial

Docker itself has been around for years and is composed of many inter-operating pieces. One of them is Docker Swarm, which allows you to declare your applications as stacks of services, and let Docker handle the rest.

In this article, Toptal Freelance Software Engineer Luke Sapan explains how to use Docker Swarm to deploy your own self-managing stack, followed by a quick example.

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Alexey Saenko
Spring Batch Tutorial: Batch Processing Made Easy with Spring

Spring Batch is a lightweight, comprehensive framework designed to facilitate the development of robust batch applications. It’s easy to set up, and even easier to use.

In this article, Toptal Freelance Software Engineer Alexey Saenko explains the programming model and the domain language of batch applications, using detailed code examples that should help any developer looking to get a head start in Spring Batch.

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Raul Jimenez Herrando
Building an Angular Video Player with Videogular

Video accounts for more than three quarters of all bandwidth used today. That’s why developers need a solid, extensible, and advanced media framework that doesn’t come with a steep learning curve.

In this tutorial, Toptal Freelance Software Engineer Raul Jimenez will introduce you to one such framework – Videogular. If you need to harness the power of Angular for HTML5 video, look no further.

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Gilad Haimov
Android DDMS: A Guide to the Ultimate Android Console

There is no way around application diagnostics. No matter how good your code is, you will need to be able to monitor and study system behavior. This is where Android’s DDMS shines.

In this article, Senior Android Engineer Gilad Haimov explains how veteran Android developers leverage the potential of DDMS to improve app stability and performance, test new features, diagnose, and debug their code.

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William Wang
Efficient React Components: A Guide to Optimizing React Performance

Why does a React web app run slow? The answer often lies in when and how frequently your components re-render, and whether those re-renders were even necessary. React doesn’t promise magical performance gains, but it provides just the right tools and functionalities to make it easy.

In this article, Toptal Freelance Software Engineer William Wang walks us through some optimization techniques that can help you build performant React web apps.

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Hanee' Medhat
Apache Spark Streaming Tutorial: Identifying Trending Twitter Hashtags

Social networks are among the biggest sources of data today, and this means they are an extremely valuable asset for marketers, big data specialists, and even individual users like journalists and other professionals. Harnessing the potential of real-time Twitter data is also useful in many time-sensitive business processes.

In this article, Toptal Freelance Software Engineer Hanee’ Medhat explains how you can build a simple Python application to leverage the power of Apache Spark, and then use it to read and process tweets to identify trending hashtags.

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Daan Terra
Virtual Reality in the Automotive Industry

From virtual showrooms to elaborate research and testing scenarios, virtual reality is starting to make its mark on the automotive industry. It can be used to educate novice drivers, train professionals operating industrial equipment, or test vehicles and drivers in extreme conditions.

In this article, Toptal Freelance Software Engineer Daan Terra shares his experiences in the field of automotive simulations, explaining how VR can fundamentally change the way cars are marketed, tested, and developed.

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Adnan Ademovic
3D Graphics: A WebGL Tutorial

Whether you just want to create an interactive 3D logo, on the screen or design a fully fledged game, knowing the principles of 3D graphics rendering will help you achieve your goal.

In this article, Toptal Freelance Software Engineer Adnan Ademovic gives us a step-by-step tutorial to rendering objects with textures and lighting, by breaking down abstract concepts like objects, lights, and cameras into simple WebGL procedures.

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Brad Peabody
Server-side I/O Performance: Node vs. PHP vs. Java vs. Go

Understanding the Input/Output (I/O) model of your application can mean the difference between an application that deals with the load it is subjected to, and one that crumples in the face of real-world uses cases. Perhaps while your application is small and does not serve high loads, it may matter far less. But as your application’s traffic load increases, working with the wrong I/O model can get you into a world of hurt.

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Daniel Angel Muñoz Trejo
How C++ Works: Understanding Compilation

Compilation and linking are two very fundamental processes that happen all the time during C++ software development. However, what happens during these processes? How does the compiler go from your neatly organized source code to a binary file that the machine understands?

In this article, Toptal Freelance Software Engineer Daniel Trejo explains how a C++ compiler works with some of the basic language constructs to answer some common questions that are related to these processes.

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Emran Bajrami
Building Cross-platform Apps with Xamarin: Perspective of an Android Developer

Writing reusable code that can be shared across multiple platforms can make developing mobile applications a lot easier. But, how do you do that without paying the usual cost of maintainability, ease of testing, and poor user experience that comes with cross-platform mobile application development?

In this article, Toptal Freelance Software Engineer Emran Bajrami walks us through Xamarin and shows us techniques for building high-quality cross-platform apps.

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Josip Šaban
SQL Server 2016 Always Encrypted: Easy to Implement, Tough to Crack

Security has always been a primary concern for database experts, and with the advent of new, decentralized services, it’s become even more crucial. Microsoft addressed the need for an added level of security in SQL with the introduction of Always Encrypted functionality in SQL Server 2016.

In this blog post, Toptal Freelance Software Engineer Josip Saban explains how Microsoft’s Always Encrypted concept works, how it’s implemented, and why developers can’t afford to ignore it.

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Nicolás J. Engler
Make Your CSS Dynamic with CSS Custom Properties

If there is something every front-end developer wants, it is proper support for variables in CSS. For years, to work around this missing feature, developers have resorted to CSS preprocessors. However, all that changes with the introduction of CSS custom properties.

In this article, Toptal Freelance Software Engineer Nicolás J. Engler walks us through CSS custom properties and shows us how they can be used to make better, more dynamic stylesheets.

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Ajinkya Deshmukh
The Salesforce Release Train: A Practical Approach to Release Management

Deploying new features with Salesforce can be problematic in more ways than one. It is crucial to have a sound strategy governing the publication of new releases, without running the risk of breaking your product.

In this post, Toptal Software Engineer Ajinkya Deshmukh will provide you with all relevant information and key tips that will allow you to manage your next Salesforce release smoothly.

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Shanglun Wang
How to Build a Natural Language Processing App

Natural language is increasingly becoming a viable way of interacting with smart software. Google search, Apple’s Siri, Microsoft’s Cortana, etc. are all capable of understanding queries in natural language.

In this article, Toptal Freelance Software Engineer Shanglun (Sean) Wang walks us through some useful concepts and techniques in natural language processing and shows how they can be used to build a simple NLP app.

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Eugene Ossipov
Genetic Algorithms: Search and Optimization by Natural Selection

Many problems have optimal algorithms developed for them, while many others require us to randomly guess until we get a good answer. Even an optimal solution becomes slow and complex at a certain scale, at which point we can turn to natural processes to see how they reach acceptable results.

In this article, Toptal Freelance Software Engineer Eugene Ossipov walks us through the basics of creating a Genetic Algorithm and gives us the knowledge to delve deeper into solving any problems using this approach.

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Diego Díaz
How to Build CSS-only Smart Layouts with Flexbox

Although CSS was meant to deal with styling, creating extraordinary layouts on the web has always been a unique challenge and almost always required the developer to resort to JavaScript. However, Flexbox is here to change that.

In this article, Toptal Freelance Software Engineer Diego Díaz walks us through the basics of Flexbox and some cool examples of how Flexbox can be used to build smart CSS-only layouts.

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Toni Kukurin
Top 10 Most Common Spring Framework Mistakes

Java’s open source Spring framework is a popular tool for creating high performing applications using plain old Java objects, but as with any tool, inappropriate use can lead to trouble. In this article, we cover the most common pitfalls of using the Spring framework so new and experienced developers alike have a roadmap of what to avoid.

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Miguel García López
Write Fat-free Java Code with Project Lombok

Java has some idiosyncrasies of its own and design choices that can make it rather verbose. While Java is a mature and performant programming language, developers frequently need to write boilerplate code that bring little or no real value other than complying with some set of constraints and conventions.

In this article, Toptal Freelance Software Engineer Miguel García López shows how Project Lombok can help dramatically reduce the amount of boilerplate code that needs to be written in a Java application.

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Eliran Goshen
Android Threading: All You Need to Know

Android provides many ways of creating and managing threads, and third-party libraries exist to make that even easier. However, with so many options, choosing the right approach can be quite confusing.

In this article, Toptal Freelance Software Engineer Eliran Goshen discusses some common scenarios in Android development that involve threading and how each of the scenarios can be dealt with.

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Ivan Pavlov
A Unit Testing Practitioner's Guide to Everyday Mockito

Using Mockito is not just a matter of adding another dependency. It requires changing how you think about your unit tests while removing a lot of boilerplate.

In this article, we’ll cover multiple mock interfaces, listening invocations, matchers, and argument captors, and see firsthand how Mockito makes your tests cleaner and easier to understand.

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Sylvain Gravel
Xamarin Forms, MVVMCross, and SkiaSharp: The Holy Trinity of Cross-Platform App Development

Developing a mobile app for multiple platforms can be quite costly. Implementing the same functionalities in multiple programming languages and dealing with a plethora of unique libraries for each platform requires a massive amount of time and knowledge.

In this article, Toptal Freelance Software Engineer Sylvain Gravel talks about Xamarin and its companion technologies that let you build mobile applications for multiple platforms without compromising familiarity, performance, and uniqueness.

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Christopher Arriola
How to Simplify Concurrency with Reactive Modelling on Android

Dealing with concurrency in Android through imperative-style programming can be quite the hassle. RxJava, a library for reactive and functional style programming, allows concurrency constructs to be modeled in a reactive way in Android’s non-reactive world.

In this article, Toptal Freelance Software Engineer Christopher Arriola shows us how RxJava can be incrementally introduced to existing Android projects and leveraged to simplify concurrency.

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Karim Sakhibgareev
PHP Frameworks: Choosing Between Symfony and Laravel

Many popular languages for web development have their ‘default’ framework, such as Ruby on Rails for Ruby, or Django for Python. However, PHP has no such single default and has multiple popular options to choose from.

In this article, Toptal Freelance Developer Karim Sakhibgareev compares the two most popular PHP frameworks, Symfony and Laravel, explores their features, and establishes guidelines for how PHP developers should choose between them.

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Paul Young
A Guide to CloudKit: How to Sync User Data Across iOS Devices

Modern mobile application development requires a well thought-out plan for keeping user data in sync across various devices. This is a thorny problem with many gotchas and pitfalls, but users expect the feature and expect it to work well. For iOS and macOS, Apple provides a robust toolkit, called CloudKit API, which allows developers targeting Apple platforms to solve this synchronization problem.

In this article, Toptal Software Engineer Paul Young demonstrate how to use CloudKit to keep a user’s data in sync between multiple clients.

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Joshua Hayden
A Guide to Robust Unit and Integration Tests with JUnit

Automated software tests are critically important to the long-term quality, maintainability, and extensibility of software projects, and for Java, JUnit is the path to automation.

While most of this article will focus on writing robust unit tests and utilizing stubbing, mocking, and dependency injection, Toptal Software Engineer Josh Hayden will also discuss JUnit and integration tests.

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Brian Coords
WordPress REST API: The Next Generation CMS Feature

For a while, WordPress seemed to had fallen behind. As the web became more reliant on JavaScript to create immersive, interactive experiences, it became increasingly clear that WordPress needed to offer new ways for users and developers to interact with its content.

In this post, Toptal Freelance Developer Brian Coords explores the amazing new features of WordPress’s REST API, showing why WordPress is still on the cutting edge of web development.

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Peter Goodspeed-Niklaus
How to Integrate OAuth 2 Into Your Django/DRF Back-end Without Going Insane

So you’ve implemented user authentication. Now, you want to allow your users to log in with Twitter, Facebook or Google. No problem. You’re only a few lines of code away from doing so.

But while there are hundreds of OAuth 2 packages that pip knows, only a few actually do what they’re supposed to do.

In this article, Toptal Software Engineer Peter Goodspeed-Niklaus explains how to integrate OAuth 2 into your Django or Django Rest Framework using Python Social Auth.

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Julien Renaux
Ionic 2 vs. Ionic 1: Performance Gains, New Tools, and a Big Step Forward

The Ionic project is rapidly gaining in popularity and is one of the most popular open source projects worldwide. With the recent announcement of the stable version of Ionic 2, this is the perfect time to underscore the Ionic 2 and its predecessor.

In this post, Toptal software engineer Julien Renaux outlines the major changes Ionic 2 brought to the platform and explains how to put these new features to good use.

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Dino Bartošak
Swift Tutorial: An Introduction to the MVVM Design Pattern

On every new project, you have the privilege of deciding how you’ll architect the app and organize the code. But if you don’t pay attention, or you rush through coding, you risk ending up with spaghetti code. The solution? Use a proper design pattern.

In this tutorial, Toptal Software Engineer Dino Bartošak explains how to implement an MVVM design pattern on a demo Swift application.

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Dmitry Ryazantsev
Time Management Secrets of an Efficient Engineer

Freelancers work flexible hours, but this convenience comes at a price: They have to manage their time better than on-site professionals. However, it also means they’re free to optimize their routine and achieve exceptional efficiency.

In this post, software engineer Dmitry Ryazantsev will guide you through the ins and outs of personal time management, leaving little to chance. What good are great rates if you waste hours each week?

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David Xu
Immutability in JavaScript using Redux

In an ever growing ecosystem of rich and complicated JavaScript applications, there’s more state to be managed than ever before: the current user, the list of posts loaded, etc.Managing state can be hard and error prone, but immutability and Redux- a predictable state container for JavaScript apps- can help significantly.

In this article, Toptal Programmer David Xu talks about managing state using immutability with Redux, a predictable state container.

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Andrej Gajdos
A Guide to Managing Webpack Dependencies

The Webpack module bundler processes JavaScript code and all static assets, such as stylesheets, images, and fonts. However, configuring Webpack and its dependencies can be cumbersome and not always a straightforward process, especially for beginners.

In this article, Toptal Software Engineer Andrej Gajdos provides a guide with examples on how to configure Webpack for different scenarios and points out the most common pitfalls connected to project dependencies and their bundling when using Webpack.

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Igor Santos
How to Build a Multilingual App: A Demo With PHP and Gettext

Making your website or web app available to a wider audience often requires it to be available in multiple languages. For non-English projects, you can increase your audience by releasing it in English as well as your native language. Internationalizing and localizing your project, however, becomes a much easier process if you start during its infancy.

In this article, Toptal Software Engineer Igor Gomes dos Santos shows us how to leverage simple tools, like Gettext and Poedit, to internationalize and localize a PHP project.

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Mateus Gondim Romão Batista
Realm Is the Best Android Database Solution

Since the inception of the platform, Android developers have had pretty much only one option for a database: SQLite. Although feature-rich and powerful, it wasn’t quite what Android app developers needed. Realm, a modern, efficient database solution for mobile platforms, turned out to be an amazing replacement for SQLite on Android.

In this article, Toptal Software Engineer Mateus Gondim Romão Batista explains why you should use Realm for your next Android application.

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Nicolás J. Engler
PostCSS: Sass’s New Play Date

PostCSS is the hot new tool that’s making the rounds on the front-end side of web development. It has been quickly and widely adopted, and possibly will have a significant impact on how we base our present-day CSS.

In this article, Toptal Software Engineer Nicolás J. Engler introduces us and guides us on how to start using this tool, expand it with plugins, or integrate with other CSS processors, task runners, or bundlers.

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Stanislav Davydov
Make Your Web Front-end Reliable with Elm

If you’ve spent your fair share of time developing web front-ends, you know that no amount of libraries and plugins are sufficient enough to make the development experience pleasant. Unpredictable event chains, complex data binding, and lack of structured data modeling only makes things worse.

Elm, a programming language built for front-end development, cuts to the root of all these problems and solves them there.

In this post, Toptal Software Engineer Stanislav Davydov provides a detailed guide to Elm and shows us how The Elm Architecture solves some of the most fundamental challenges of front-end development.

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Jack Kinsella
The Art of Building Self-Service Admin Areas

Software is regular and predictable, so it seems paradoxical that practically every web app needs a sizable administrative area. The explanation for this paradox lies in software’s interaction with humans. While you probably can’t build a fully automated system, there’s a lot you can do to save time and money.

In this post, Entrepreneur Jack Kinsella explains what you can do to streamline administration, thus saving valuable time and making your projects more profitable. Adminimisation is the word of the day!

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Donald Mudenge
Don't Hate WordPress: 5 Common Biases Debunked

Today, WordPress covers more than 50 percent of website shares and serves nearly 60 million websites worldwide. Its popularity has resulted in many misconceptions that have grown and spread like a forest fire, and have made people stay away from WordPress.

In this post, Toptal Software Engineer Donald Mudenge explains the five most common WordPress taboos and myths, clarifies them, and offers solutions on how to overcome them.

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Luka Blažecki
A Node.js Guide to Actually Doing Integration Tests

Your software isn’t fully tested until you write integration tests for it. While unit tests help ensure that functions are properly written, integration tests help ensure that the system is working properly as a whole.

In this article, Toptal Software Engineer Luka Blažecki uses Node.js to explain why integration testing is important for every development platform and how to write clean, composable integration tests.

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Ratko Solaja
The Ultimate Guide to Building a WordPress Plugin

WordPress plugins can be both a blessing and a curse. With more than 45,000 plugins available in its official repository, WordPress users can customize their website to their heart’s content. However, not all plugins follow the standards necessary to keep the platform performant and secure while also delivering a solid user experience.

In this tutorial, Toptal Software Engineer Ratko Solaja shows us how to build a robust WordPress plugin, following all the necessary best practices.

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Demir Selmanovic
How to Make an Android and iOS App in C# on a Mac

In the past few years, Microsoft has pulled a few aces from up its sleeve. Yes, they messed up Skype, failed with smartphones, and almost succeeded with tablets. But, they did some really amazing things as well.

Relinquishing their closed empire approach, they open-sourced .NET, joined the Linux Foundation, released SQL Server for Linux, and created this great new tool called Visual Studio for Mac.

In this post, Head of Open Source Demir Selmanovic details how to make an Android and iOS app in C# on your Mac.

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Mohammad Altarade
The Definitive Guide to NoSQL Databases

Limited SQL scalability has prompted the industry to develop and deploy a number of NoSQL database management systems, with a focus on performance, reliability, and consistency. The trend was driven by proprietary NoSQL databases developed by Google and Amazon. Eventually, open-source systems like MongoDB, Cassandra, and Hypertable brought NoSQL within reach of everyone.

In this post, Toptal Software Engineer Mohamad Altarade dives into some of them and explains why NoSQL will probably be with us for years to come.

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Martín Di Felice
The Advanced Guide to Optimizing WordPress Performance

WordPress, one of the most popular publishing platforms, has stood the test of time and now powers a significant portion of the web. Sadly, its reputation is plagued by claims of poor performance and complexity with scaling. However, the root causes of such performance issues are often bad code and poorly implemented plugins and themes.

In this post, Toptal Software Engineer Martín Di Felice shares tips and tricks for WordPress developers who want to build better plugins and themes and destroy the notion that WordPress is a slow platform.

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Eqbal Quran
Build Sleek Rails Components With Plain Old Ruby Objects

Your website is gaining traction, and you are growing rapidly. Ruby/Rails is your programming language of choice. Your team is bigger and you’ve given up on “fat models, skinny controllers” as a design style for your Rails apps. However, you still don’t want to abandon using Rails? No problem.

In this article, Toptal Software Engineer Eqbal Quran explains how you can decouple and isolate your Rails components using nothing Plain Old Ruby Objects. Ruby objects and abstractions can decouple concerns, simplify testing, and help you produce clean, maintainable code.

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Ken Hu
A Data Engineer's Guide To Non-Traditional Data Storages

With the rise of big data and data science, storage and retrieval have become a critical pipeline component for data use and analysis. Recently, new data storage technologies have emerged. But the question is: Which one should you choose? Which one is best suited for data engineering?

In this article, Toptal Data Scientist Ken Hu compares three prominent storage technologies within the context of data engineering.

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Alexander Gaidukov
An Introduction to Protocol-oriented Programming in Swift

Most modern programming languages, in the hopes of enhanced maintainability and reusability of code, offer some constructs that help the developer keep the definition of behavior and its implementation separate.

Swift takes the idea of interfaces a step further with protocols. With protocols and protocol extensions, Swift allows developers to enforce elaborate conformity rules without compromising the expressiveness of the language.

In this article, Toptal Software Engineer Alexander Gaidukov explores Swift protocols and how protocol-oriented programming can improve the maintainability and reusability of your code.

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David Fox
The Zen of devRant

Let’s face it: Sometimes you just need to rant. Fortunately, there’s an app for that. It’s called devRant, and it’s the place for developers to vent about clients from hell, non-technical friends and family, and clueless recruiters.

In this roundup, devRant Co-Founder David Fox shares his favorite collection of rants since launching. Some will make you laugh. Others will make you laugh so hard you cry. And just about all of them will make you empathize with the author.

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Vedran Aberle Tokić
To Designers With Love (A Letter From a Front-end Developer)

If you’re a veteran frontender, you’ve probably had some not-so-great experiences with designers, and chances are some designers have had an equally bad experience working with you. How can you make sure you get exactly what you need from your designer, without placing an undue burden on them?

It’s a tall order, but in this article Freelance Software Engineer Vedran Aberle Tokic outlines and addresses a number of potential issues that may become roadblocks for your execution. Implementing these suggestions may result in overhead for designers, but they can save enormous amounts of time and headache elsewhere.

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Marian Paul
Migrate Legacy Data Without Screwing It Up

Nobody wants to leave valuable customer data behind. Unfortunately, though, the hardest part of data migration to a complex CRM system, such as Salesforce, is the handling of legacy data.

In this article, Toptal Software Engineer Marian Paul provides 10 tips for successful legacy data migration to Salesforce.

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Alexander Gaidukov
How to Isolate Client-Server Interaction Logic in iOS Applications

Client-server interactions play a vital role in most modern mobile applications. By leveraging available backend services these mobile applications can provide some really amazing functionalities. However, as mobile applications grow complex it becomes essential to keep the networking module as clean and maintainable as possible - separated from the rest of the application logic.

In this article, Toptal freelance software engineer Alexander Gaidukov walks us through the design of a simple networking module that allows your iOS application to interact with RESTful APIs.

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Dallas H. Snider
An HDFS Tutorial for Data Analysts Stuck With Relational Databases

The Hadoop Distributed File System (HDFS) is a scalable, open source solution for storing and processing large volumes of data. With its built-in replication and resilience to disk failures, HDFS is an ideal system for storing and processing data for analytics.

In this step-by-step tutorial, Toptal Database Developer Dallas H. Snider details how to migrate existing data from a PostgreSQL database into the more efficient HDFS.

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Zhuyi Xue
A Comprehensive Introduction To Your Genome With the SciPy Stack

Genome data is one of the most widely analyzed datasets in the realm of Bioinformatics. The SciPy stack offers a suite of popular Python packages designed for numerical computing, data transformation, analysis and visualization, which is ideal for many bioinformatic analysis needs.

In this tutorial, Toptal Software Engineer Zhuyi Xue walks us through some of the capabilities of the SciPy stack. He also answers some interesting questions about the human genome, including: How much of the genome is incomplete? How long is a typical gene?

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Nilson Souto
The Mistakes Most Swift Developers Don't Know They're Making

Swift is the new programming language created to be a modern replacement for Objective-C in iOS and OS X application development. In general, a skilled Swift developer is usually someone who is already experienced with Objective-C, and that, among other things, might lead them to write Swift code using Objective-C best practices, which can cause some bad mistakes.

In this article, Toptal Freelance Software Engineer Nilson Souto outlines the most common mistakes Swift developers should be aware of.

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Gilad Haimov
An Overly Thorough Guide To Underused Android Libraries

Any experienced developer will tell you that their best code isn’t code they wrote. It’s code they took from someone else’s work. Many of the problems we encounter have already been solved—and the remedies packaged into libraries available to anyone. Why reinvent the wheel when free wheels are everywhere?

In this guide, Senior Android Engineer Gilad Haimov will take you on a quick tour of some the most powerful Android libraries out there. Robust as a hammer, faster than a drill, and more precise than any scalpel; no Android developer should leave home without these must-have tools.

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Nermin Hajdarbegovic
Android 7.0 for Developers: New Features, Performance Upgrades & Other Stuff You Won’t Care About

Google formally announced Android 7.0 a few weeks ago, but as usual, you’ll have to wait for it. Thanks to the Android update model, most users won’t get their Android 7.0 over-the-air (OTA) updates for months. However, this does not mean developers can afford to ignore Android Nougat.

In this article, Toptal Technical Editor Nermin Hajdarbegovic takes a closer look at Android 7.0, outlining new features and changes. While Android 7.0 is by no means revolutionary, the introduction of a new graphics API, a new JIT compiler, and a range of UI and performance tweaks will undoubtedly unlock more potential and generate a few new possibilities.

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Nikita Tuk
The 10 Most Common Mistakes iOS Developers Don't Know They're Making

Apple’s iOS is the second-largest mobile operating system in the world. It also has a very high adoption rate, with more than 85 percent of users on the latest version. These highly engaged users have high expectations: If your app has bugs, you’ll hear about it. And once the one-star reviews start rolling in, it’s hard to recover.

In this article, Toptal Software Engineer Nikita Tuk outlines the 10 most common mistakes that developers make—and how to avoid them.

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Eric Grosse
Webpack or Browserify & Gulp: Which Is Better?

Gone are the days where front-end developers for web applications could use ad-hoc JavaScript with jQuery and such all in a single JavaScript file. Modern web applications require more effort from the developer to adopt an overall architecture and development process. Building such front-end applications relies on lots of external dependencies and modular source code, and these elements necessitate automation to save developers time and reduce the chances of mistakes.

In this article, Toptal Freelance Software Engineer Eric Grosse shows us how various combinations of the popular tools Webpack, Browserify, Gulp and Npm can benefit us by enhancing our development environment and allowing us to focus on writing the app itself.

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Daniel Ivanov
How To Improve ASP.NET App Performance In Web Farm With Caching

Caching is a powerful technique for increasing performance, but the whole idea behind caching works only as long as the result we cached remains valid. And here we get to the hard part of the problem: How do we determine when a cached item has become invalid and needs to be recreated?

In this article, Toptal Freelance Software Engineer Daniel Ivanov provides an ASP.NET-based solution to replace invalid cached items and assure high throughput and performance of web applications designed to handle a high load.

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Punit Jajodia
The Definitive Guide to DateTime Manipulation

In the realm of software development, time and date manipulation is considered by many to be a difficult task. Complicated time zone rules, leap seconds, differences in locale-specific formatting, etc., force us to immediately resort to popular time and date manipulation libraries. We often use these libraries without thinking about how exactly they work, which can lead to all sorts of obscure bugs in our software.

In this article, Toptal Freelance Software Engineer Punit Jajodia gives us an in-depth introduction to some concepts and best practices to avoid a few of the obvious issues related to changing the time and date in our applications.

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Grzegorz Gajos
How Hibernate Almost Ruined My Career

Are you building the next big thing? Planning to become the next Facebook or Google? Are you at the point of making fundamental decisions that will stay with you for the entire project? There is a good chance that you will pick a robust language like Java. If so, you want to pick the best object-oriented abstraction of your flexible data model because you don’t want to deal with plain SQL. You want to support all kinds of data and ideally, support all kind of databases. If so, there’s is only one right choice for you: Hibernate.

Continue reading the story written by Freelance Software Engineer Grzegorz Gajos, about one of these imaginary but entirely possible scenarios.

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Boško Ivanišević
How Sequel and Sinatra Solve Ruby’s API Problem

The rise of the web and mobile applications has led to an increased need for back-end API services. Ruby on Rails’ philosophy seemingly makes it the ideal framework for creating back-end APIs. However, using Rails only for the API is overkill.

In this article, Freelance Software Engineer Boško Ivanišević explores alternatives to Rails and introduces us to two very mature and powerful gems, Sinatra and Sequel, which in combination provide powerful tools for creating server-side APIs.

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Andrew Schultz
The 10 Most Common Mistakes That WordPress Developers Make

WordPress is easily the most powerful open source blogging and content management system available online today. As WordPress is easy enough to set up and has a user-friendly approach, many developers are often underestimating it and so make mistakes in development.

In this article, Toptal Freelance Software Engineer Andrew Schultz outlines the ten most common mistakes that WordPress developers should be aware of for future projects.

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Zachary Goldberg
The Six Commandments of Good Code: Write Code that Stands the Test of Time

How do you define good code? Is it 100% test coverage, or is it backwards compatibility with decade-old hardware? We may not be able to reach an end to this debate yet, but good software always seems to conform to a few certain qualities of code.

In this article, Toptal Freelance Software Engineer Zachary Goldberg walks us through six simple ideas that can help you make better, more maintainable software.

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Christopher Arriola
Meet RxJava: The Missing Reactive Programming Library for Android

Implementing applications that deal with complex concurrent behavior has always been a challenging aspect of programming. Various paradigms exist that promise a solution to this problem in different ways. RxJava is a Java library that enables Functional Reactive Programming in Android development. It raises the level of abstraction around threading in order to simplify the implementation of complex concurrent behavior.

In this article, Toptal Freelance Software Engineer Christopher Arriola gives us a detailed walkthrough of RxJava and how it fits into the realm of Android development.

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Nermin Hajdarbegovic
Celebrating 25 Years of Linux Kernel Development

Linux is now 25 years old, but it’s no hipster. It’s not chasing around Pokemon, and it’s not moving back in with its parents due to crippling student debt. In fact, Linux is still growing and evolving, but the core ideas of the Linux State of Mind remain the same.

In this article, Toptal Technical Editor Nermin Hajdarbegovic takes a look at the history of Linux development, the state of Linux today, and what’s next for the world’s most popular open-source operating system.

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Ivan Kušt
Ten Kotlin Features To Boost Android Development

Kotlin is a new, expressive general-purpose programming language powered by the same virtual machine technology that powers Java. Since Kotlin compiles to the JVM bytecode, it can be used side-by-side with Java, and it does not come with a performance overhead.

In this article, Toptal Freelance Software Engineer Ivan Kušt gives us a walkthrough of ten major features of Kotlin that help avoid boilerplate code and, more importantly, save time.

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Matko Šuflaj
Java in the Cloud: Continuous Integration Setup Tutorial

More than two decades ago, Java shook the world with its “Write once, run anywhere“ slogan. Today, Java developers have at their disposal a whole set of tools, such as Spring Boot, Docker, Cloud, Amazon Web Services, and Continuous Delivery, to take development and delivery to a whole new universe.

In this article, Toptal Freelance Software Engineer Matko Šuflaj presents all these technologies and guides us through a step-by-step tutorial on how to build a small microservice and prepare it for continuous integration in the cloud.

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Johannes Stein
The Duel: React Native vs. Cordova

As a result of smartphones and mobile applications becoming so popular, web developers have been looking for ways to create mobile applications using JavaScript. This increased demand has led to the development of many JavaScript frameworks capable of running native-like applications on mobile devices.

In this article, Toptal Freelance Software Engineer Johannes Stein compares the current two most popular choices for mobile-oriented JavaScript frameworks, Cordova and React Native. Examining their advantages and pitfalls, he dives into details of each and compares them across different disciplines.

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Nermin Hajdarbegovic
Spectacular Crowdfunding Fails And Their Impact On Entrepreneurship

What’s the biggest problem with crowdfunding today? Everyone wants a sweet slice of the crowdfunded pie, but nobody wants a single crumb of responsibility. As a result, crowdfunding platforms, the tech press, and the geek public have picked up a track record filled with spectacular crowdfunding failures.

In this article, Toptal Technical Editor Nermin Hajdarbegovic takes a look at the state of crowdfunding today and explains why the industry needs to do more to clean up its act and get rid of bad apples in crowdfunding.

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Gregor Ambrozic
Why Should Java Developers Give Grails a Chance?

Java may have stood the test of time, but it can still be a source of great frustration among many web developers. Dealing with its verbosity and infrastructure overhead, for example, can take hours, even for the most basic needs.

In this article, Toptal Freelance Software Engineer Gregor Ambrozic shows us how Grails and its many appealing features can be a viable alternative to traditional Java web applications frameworks.

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Boris Barroso
Meet Ecto, The No-Compromise Database Wrapper For Concurrent Elixir Apps

Elixir, with its simple and clean syntax, makes building scalable and maintainable concurrent applications a breeze. Ecto is a database wrapper that lives up to the high expectations set by Elixir’s reputation. Its domain-specific language provides a pleasant way to interact with databases and build fault-tolerant, concurrent applications in Elixir with ease.

In this article, Toptal Freelance Software Engineer Boris Barroso walks us through Ecto and its four main components: Repo, Schema, Changeset and Query.

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Behsaad Ramez
Social Network APIs: The Internet’s Portal to the Real World

Social networks are a rich source of user information. From a person’s current mood to endless streams of photos, there is by now probably a social network for each aspect of human life. From the development side, access to users’ information can be an essential element in providing a truly personalized experience in any application.

In this article, Toptal Freelance Software Engineer Behsaad Ramez shows us how the APIs of some of these social networks stack against each other and how they may be leveraged to accumulate precious information about users.

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Andrey Shalitkin
Write Tests That Matter: Tackle The Most Complex Code First

In today’s world, code is expected to change as quickly as requirements do, and tests play an important role in making that possible. Many modern projects boast great test coverage, making them more resilient to regression issues. However, that is not true for all projects - especially some legacy projects which have little in the way of testing.

In this article, Toptal Freelance Software Engineer Andrey Shalitkin discusses two metrics, coupling and cyclomatic complexity, that are important in identifying which portions of code to include in test coverage.

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André William Prade Hildinger
How to Build a Multitenant Application: A Hibernate Tutorial

In the realm of enterprise software, especially for software provided as a service, multitenancy ensures that data is truly isolated for each client within a shared instance of software. Among its numerous benefits, multitenancy can greatly simplify release management and cut down costs.

In this article, Toptal Freelance Software Engineer André William Prade Hildinger shows us how Hibernate, a persistence framework for Java, makes implementing a multitenant Java EE application easier than it sounds.

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Francis Altomare
A New Way of Using Email for Support Apps: An AWS Tutorial

Of all the modern ways people talk to each other, email seems to have stood the test of time and is arguably still one of the most effective and widely used means of communication. Thus, being able to programmatically send and receive emails can open new dimensions to a user’s experience of software that powers human communication.

In this article, Toptal Freelance Software Engineer Francis Altomare shows us how he leveraged various Amazon Web Services technologies to build a simple communication application in which email itself is an important interface.

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Nermin Hajdarbegovic
Boost Your Productivity With Clever Travel Hardware

You can buy capri pants, cheap flip-flops, and boonie hats anywhere on vacation, but beachside shops usually don’t carry quality hardware that can help you be more productive on the road or save you time and money for more enjoyable activities.

In this post, Toptal Technical Editor Nermin Hajdarbegovic takes a look at inexpensive and readily available travel hardware designed to boost your productivity on the road. You can put most of these gadgets on your summer shopping list without making a dent in your travel budget.

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Bruz Marzolf
Hunting Down Memory Issues In Ruby: A Definitive Guide

Memory issues in programs can be quite frustrating whether you’re the user or the developer attempting to solve the problem. In Ruby, the garbage collector plays a vital role in managing your program’s memory so that you can focus on other important things. However, it is often possible to overwhelm the garbage collector or end up with sneaky resources that cannot be freed, which can lead to all sorts of memory issues.

In this article, Toptal Freelance Software Engineer Bruz Marzolf explains why certain memory issues arise in Ruby applications and how to tackle them easily.

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Tomasz Czura
Introduction to Kotlin: Android Programming For Humans

Java has been a dominant programming language for ages, but modern times call for modern languages. Meet Kotlin, a modern, clear, and expressive programming language powered by the same virtual machine technology that powers Java.

In this article, Toptal Freelance Software Engineer Tomasz Czura takes us for a spin through the world of Kotlin and shows us how it can be used to make an Android application with an elegant architecture without compromising the very qualities of the code that Kotlin aims to provide.

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Tibor Kaputa
Tips And Tools For Optimizing Android Apps

The plethora of tutorials on building Android apps may have you thinking that making a mobile app is simple. In reality, however, performance issues can be very complicated, and because performance plays a key role in making sure that your app stays on your users’ list of favorite apps for a long time, every little detail must be given one’s full attention.

In this article, Toptal Freelance Software Engineer Tibor Kaputa shares some tips on how you can optimize some common performance issues and identify some of the bottlenecks in your Android app.

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Gabriel Aszalos
Testing Your Go App: Get Started The Right Way

When Golang first came out, there were next to no resources available about how to efficiently test your Go-written application. Even now, with plenty of guides and recommendations available, many bright-eyed developers still try to apply their Ruby or JavaScript mindset and use external frameworks to test apps written in Go.

In this article, Toptal Freelance Developer Gabriel Aszalos first explains Golang philosophy and then covers the basics of testing in Go, from table testing to JSON response assertion.

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Michele Sciabarra
Scaling Scala: How to Dockerize Using Kubernetes

Are you a Scala developer hoping to scale your application in the cloud? If so, meet Kubernetes, a cluster manager for Docker applications. Developed by Google, it’s the latest in new open source tools making major waves.

In this article, Toptal Freelance Software Engineer Michele Sciabarra guides us through a step-by-step tutorial on how to take a generic Scala application and implement Kubernetes and Docker to launch multiple instances of the application.

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Anton Kanevsky
Gulp: A Web Developer's Secret Weapon for Maximizing Site Speed

When dealing with web-based projects that run in the production environment, being able to build and deploy changes quickly is a top priority. However, repetitive processes such as building front-end assets, when not automated, can be prone to critical errors.

In this article, Toptal Freelance Software Engineer Anton Kanevsky shows us how Gulp can solve various challenges of build automation through simple JavaScript routines.

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Jan Gorecki
Boost Your Data Munging with R

As a language, R is strongly tied to data and is thus used mostly by statisticians and data scientists. Many who already use R for machine learning, though, are not aware that data munging can be done faster in R, meaning another tool is not required for that task.

In this article, Freelance Software Engineer Jan Gorecki explores tabular data transformations and introduces us to one of the fastest open-source data wrangling tools available.

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Ethan James
Get Your Angular 2 On: Upgrading from 1.5

“So much of what’s new and exciting about Angular 2 is its new way of thinking rather than its new architecture,” says Toptal Freelance Developer Ethan James.

In this article, Ethan walks through the inner workings of a simple Angular 1.5 app and then shows us how to upgrade it to Angular 2 while giving us the necessary understanding to truly appreciate it.

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Joaquín Aldunate
Web Audio API: Why Compose When You Can Code?

Meet Web Audio API, a powerful programming interface for controlling audio on the web. Gone are the days when the web browser could rarely play a sound file correctly. With this API, you can now load sound from different sources, apply effects, create visualizations, and do much more.

In this article, Toptal Freelance Software Engineer Joaquín Aldunate shows us how to unleash our inner musician using Web Audio API with the Tone.js framework by giving us a brief overview of what this API has to offer and how it can be used to manipulate audio on the web.

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Jeremy Greer
Write Code to Rewrite Your Code: jscodeshift

How many times have you used the find-and-replace functionality (or RegEx) across a directory to make changes to JavaScript source files? Up your refactoring game by using codemods, scripts used to rewrite other scripts.

In this article, Toptal Freelance Developer Jeremy Greer walks us through three common uses of codemods, using the toolkit “jscodeshift”.

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Sergey Reznick
Get Your Hands Dirty With Scala JVM Bytecode

The Scala language has continued to gain popularity over the last several years, thanks to its excellent combination of functional and object-oriented software development principles, and its implementation on top of the proven Java Virtual Machine (JVM).

Creating a language that compiles to Java bytecode requires a deep understanding of the inner workings of the Java Virtual Machine. To appreciate what Scala’s developers have accomplished, it is necessary to go under the hood, and explore how Scala’s source code is interpreted by the compiler to produce efficient and effective JVM bytecode.

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Andrea Nalon
The Rise Of Automated Trading: Machines Trading the S&P 500

More than 60 percent of trading activities with different assets rely on automated trading and machine learning instead of human traders. Today, specialized programs based on particular algorithms and learned patterns automatically buy and sell assets in various markets, with a goal to achieve a positive return in the long run.

In this article, Toptal Freelance Data Scientist Andrea Nalon explains how to predict, using machine learning and Python, which trade should be made next on the S&P 500 to get a positive gain.

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Justin Brazeau
Sass Mixins: Keep Your Stylesheets DRY

Nowadays, front-end development workflows involve many modern tools and preprocessors that not only streamline the whole process, but also allow you to spend less time on common web tasks, giving you more time to focus on other aspects of the project that require more careful and skilled insight. Sass, the scripting language for syntactically awesome stylesheets, comes with robust and built-in support for mixins - an essential feature for keeping your stylesheets DRY.

In this article, Toptal Freelance Software Engineer Justin Brazeau shows us 10 useful Sass mixins that help keep your stylesheets manageable by breaking them into smaller reusable bits, each with its own focus.

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Vasily Koval
Jumpstart Your PHP Testing with Codeception

Would you like to test your PHP code like a boss? Do you feel that basic unit tests and PHPUnit just don’t cut it anymore? If your answer to both questions is yes, you might want to try Codeception, a mature and well-documented testing framework designed to outperform PHPUnit and Behat.

In this post, Toptal Freelance Software Engineer Vasily Koval describes how he came to take the plunge and start using Codeception, and he explains why you should check out Codeception for your PHP testing needs.

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Tomas Macek
The 10 Most Common Mistakes That Unity Developers Make

Unity is an excellent and straightforward tool to use for multi-platform development. Its principles are easy to understand, so programmers can start developing new products quickly and intuitively. However, if developers do not keep some important things in mind, development can slow down at crucial points, including when the project moves away from initial prototype or is approaching final release.

In this article, Toptal Freelance Software Engineer Tomas Macek outlines the most common mistakes that Unity developers should be aware of for future projects.

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Lovro Iliassich
Clustering Algorithms: From Start To State Of The Art

Clustering algorithms are very important to unsupervised learning and are key elements of machine learning in general. These algorithms give meaning to data that are not labelled and help find structure in chaos. But not all clustering algorithms are created equal; each has its own pros and cons.

In this article, Toptal Freelance Software Engineer Lovro Iliassich explores a heap of clustering algorithms, from the well known K-Means algorithm to the elegant, state-of-the-art Affinity Propagation technique.

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Jesus Dario Rivera
Toptal's Quick And Practical JavaScript Cheat Sheet: ES6 And Beyond

Software engineers are always searching for the best tools and guides to help them be more productive and allow them to spend less time reading long technical specifications.

Today, Toptal is pleased to present a new resource to the community: the JavaScript Cheat Sheet - ES6 and Beyond. Toptal’s JavaScript Cheat Sheet is a quick, easily understandable reference guide. It is free to download and includes all the new and exciting features introduced with ES6 as well as the future experimental features from ES7.

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Bhushan Lodha
HTTP Request Testing: A Developer's Survival Tool

It’s tragically common for developers to come into a project where proper automated testing has been and will continue to be overlooked. It’s a situation Freelance Developer Bhushan Lodha has found himself in all too often; fortunately, he’s found a solution. In this article, he briefly covers the reasons why testing is overlooked and ultimately explains his “coding life hack” to ensure quality control even when he can’t introduce a testing framework.

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Chuoxian Yang
Express, Koa, Meteor, Sails.js: Four Frameworks Of The Apocalypse

Some platforms have an overwhelming number of options for web frameworks. Node.js, the event-driven server-side JavaScript environment, is one such platform. Whether it’s the minimalist Express or the full-blown MVC web framework Sails.js, Node.js seems to have it all.

In this article, Toptal Freelance Software Engineer Chuoxian Yang explores four of the most popular Node.js web frameworks and discusses how each framework stands out from the rest of the crowd in Node.js.

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Federico Pereiro
Declarative Programming: Is It A Real Thing?

In a nutshell, declarative programming consists of instructing a program on what needs to be done, instead of telling it how to do it. This approach involves providing a domain-specific language (DSL) for expressing what the user wants. This DSL shields users from messy low-level constructs while still achieving the desired end-state.

While declarative programming offers advantages over the imperative approach it replaces, it’s not as straightforward as it may seem. In this comprehensive article, Toptal Freelance Software Engineer Federico Pereiro outlines his experience with declarative tools and explains how you can make declarative programming work for you.

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Michele Sciabarra
Using Scala.js With NPM And Browserify

Today, writing applications in languages that compile to JavaScript is a very common practice. Scala developers, for example, can use Scala.js and have the same language for both the server and the client. That said, Scala’s compiler and standard dependency management tools are too limiting in the modern JavaScript world.

In this article, Toptal Freelance Software Engineer Michele Sciabarra shows us how to integrate Scala.js with the plethora of JavaScript modules available on NPM, using tools like Browserify, and explains how to do this without even having to install Node.js.

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Marko Dvečko
Introduction To Concurrent Programming: A Beginner's Guide

Concurrency allows programs to deal with a lot of tasks at once. But writing concurrent programs isn’t a particularly easy feat. Dealing with constructs such as threads and locks and avoiding issues like race conditions and deadlocks can be quite cumbersome, making concurrent programs difficult to write.

In this article, Toptal Freelance Software Engineer Marko Dvečko gives us an overview of some concurrent programming models. He explains how each of these models gives structure to the programs we write and shows how to avoid certain concurrency issues that can come with these models.

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Jesus Dario Rivera
Programming Visually With Node-RED: Wiring Up The Internet Of Things With Ease

Node-RED, built on Node.js, is a tool designed for programming visually without having to write any code. It comes equipped with a browser-based flow editor that allows hardware devices and APIs to be connected with each other easily, making it an ideal tool for rapidly developing programs for IoT devices.

In this article, Toptal freelance software engineer Jesús Darío Rivera walks us through the process of building a simple program using Node-RED and Netbeast along with a virtual light bulb plugin that mimics the capabilities of a real smart bulb.

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Tomislav Matijević
Introduction To BEM Methodology

When building smaller websites, the way developers structure their CSS code is usually not a big issue. However, when it comes to larger, more complex projects, code organization becomes crucial.

In this article, Toptal Freelance Software Engineer Tomislav Matijević introduces us to BEM methodology and explains how this CSS practice can massively improve code maintainability, speed up the development process, and streamline the teamwork of developers by arranging CSS classes into independent modules.

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Mikhail Angelov
Gulp Under the Hood: Building a Stream-based Task Automation Tool

Streams are a powerful construct in Node.js and in I/O driven programming in general. Gulp, a tool for task automation, leverages streams in elegant ways to allow developers to enhance their build workflow.

In this article, Toptal engineer Mikhail Angelov gives us some insight into how Gulp works with streams by showing us step-by-step how to build a Gulp-like build automation tool.

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Ethan James
You Need a Hero: The Project Manager

For every tech project or business, there’s inevitably the “client” and the “programmer”. Sometimes they make it work between themselves, but often someone has to step in to establish the ground rules, keep everyone honest, and facilitate communication between all parties.

This someone, this hero, is the project manager.

In this entertaining article, Ethan James gives his insights as to why you, the developer, and you, the client, should invest in a project manager… or at least employ the techniques outlined.

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Ahmed AbdelRazzak
Clean Code and The Art of Exception Handling

Exceptions are as old as programming itself. An unhandled exception may cause unexpected behavior, and results can be spectacular. Over time, these errors have contributed to the impression that exceptions are bad.

But exceptions are a fundamental element of modern programming. Rather than fearing exceptions, we should embrace them and learn how to benefit from them. In this article, we will discuss how to manage exceptions elegantly, and use them to write clean code that is more maintainable.

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Nermin Hajdarbegovic
HSA For Developers: Heterogeneous Computing For The Masses

HSA is a set of standards and specifications designed to allow further integration of CPUs and GPUs on the same bus. This is not an entirely new concept, but HSA takes it to the next level. HSA would effectively take the developer out of the equation, at least when it comes to assigning different loads to different processing cores.

In this post, Toptal Technical Editor and resident chip geek Nermin Hajdarbegovic takes a closer look at HSA and the future of heterogeneous computing in general. Get ready for some good news, but don’t forget to brace for bad news first.

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Kleber Virgilio Correia
Getting Started with Elixir Programming Language

Elixir, a dynamic, functional programming language, is designed for building scalable and maintainable applications with a simple, modern, and tidy syntax. Although it is easy to understand, Elixir’s approach to concurrency and its data type nuances require some getting used to.

In this article, Toptal engineer Kleber Virgilio Correia gives us a comprehensive guide to the various basic data types in that are available in Elixir.

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Tomislav Bacinger
Toptal's Quick and Practical CSS Cheat Sheet

As software engineers, we’re always searching for the best tools and guides that will help us to be more productive while spending less time searching and reading long technical specifications.

Today, Toptal is pleased to present an entirely new resource to the community as a free download: a CSS Cheat Sheet. Toptal’s CSS Cheat Sheet is a quick CSS reference guide, and includes CSS syntax, the most important selectors, properties, sizes, and units, and other useful CSS details, all in a short, easily understandable format.

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Nermin Hajdarbegovic
Rethinking Authentication And Biometric Security, The Toptal Way

How does one secure a vast, distributed network of tech talent? There are three ways of doing this: the right way, the wrong way, and the Toptal way. Today, we will be discussing the latter, and unveiling our plans for a comprehensive overhaul of our onboarding and authentication procedures.

In this post, Toptal Technical Editor Nermin Hajdarbegovic will help you get acquainted with our brand new processes. Since all Toptalers will be required to use our new security platform, we encourage you to comment and contribute to our efforts.

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Mihai Cozma
Mastering 2D Cameras in Unity: A Tutorial for Game Developers

Camera systems are very important in conveying the right atmosphere in video games. When developing games, even 2D ones, advanced cameras should be your tool of choice.

In this article, Toptal engineer Mihai Cozma shows us how to build a modular camera system for 2D platform games using some simple components in Unity that can be easily extended to 2.5D or even 3D games.

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Julien Renaux
The 9 Most Common Mistakes That Ionic Developers Make

Ionic is extremely popular at the moment, and it has revolutionized the hybrid application industry in a way that nobody could have imagined. However, over time, the best practices and tooling for Ionic have not progressed in the same way. As a result, the number of pitfalls that developers need to look out for when working with Ionic is still high.

In this article, Toptal Freelance Software Engineer Julien Renaux outlines the most common mistakes that Ionic developers should know.

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Jongwook Kim
How to Create a Simple Python WebSocket Server Using Tornado

The threaded model and global interpreter lock has always been in the way of Python handling thousands of concurrent long-lived connections. Modern web frameworks, such as Tornado, use non-blocking network I/O to make Python feasible for implementing WebSocket servers.

In this article, Toptal engineer Jongwook Kim walks us through the process of implementing a simple WebSocket-based web application in Python using the Tornado web framework.

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Rohit Boggarapu
A Tutorial on Drill-down FusionCharts in jQuery

When dealing with data analysis, most companies rely on MS Excel or Google Sheets, but dealing with data presented this way isn’t very eye-catching or intuitive. It’s once you add visualizations to this data that things become a little easier to manage. That’s the topic of today’s tutorial by our guest author from Adobe, Rohit Boggarapu. Join us as he guides us though the process of making interactive drill-down charts using jQuery and FusionCharts.

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Minhao Zhang
Boost Your Productivity With Amazon Web Services

In the rapidly evolving Internet world, getting things done fast is always critical. Still, developers today waste hundreds of hours on tasks not related to programming: setting up databases or caches, deploying projects, monitoring online statistics, and so on.

In this article, Toptal Freelance Software Engineer Minhao Zhang guides us in a step-by-step tutorial on how to reduce waste by setting up your first virtual machine using Amazon Web Services, and introduces the most widely used AWS services that can boost your productivity in minutes.

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Joshua Mock
Writing Testable Code in JavaScript: A Brief Overview

Writing code that is easily testable takes some effort and planning. However, some patterns exist that can be used to write simple and functional code, making it easier to test them when the time comes.

In this article, Toptal engineer Joshua Mock shares some useful tips and patterns for writing testable code in JavaScript that are both simple to understand and simple to implement.

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Becze Szabolcs
Android Developer’s Guide to Fragment Navigation Pattern

Navigation in mobile applications, when done right, can have tremendous positive impact on overall user experience. Android offers application developers multiple ways of implementing navigation in their application. However, not all navigation patterns are created equal.

In this article, Toptal engineer Becze Szabolcs shows us how to implement fragment-based navigation and how it stacks up against Android’s traditional navigation philosophy.

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Andrei Smirnov
How to Bootstrap and Create .NET Projects

To create a .NET project from scratch, simply using Visual Studio Wizard is good enough most of the time. However, the default project settings produced by wizards are hardly acceptable for professional teams, as they set too low of a bar on quality.

In this article, Toptal Freelance Software Engineer Andrei Smirnov guides us through several standard practices, configuration files, and project settings every developer should apply when starting a new .NET project. Doing this in the very beginning of a project decreases future technical debt and makes product source code readable and professional-looking.

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Vilson Duka
Introduction To PHP 7: What's New And What's Gone

If you haven’t been working with PHP lately, you might wonder what happened to PHP 6. Why the skip from PHP 5 to PHP 7? Well, long story short, PHP 6 was a failure. To avoid confusion, the new version was renamed PHP 7.

PHP 7 introduces a number of new features, while at the same time dropping depreciated SAPIs and extensions. As a result, it tends to outperform PHP 5.x by a wide margin. Some compatibility issues could pose a problem, but most developers have nothing to worry about.

In this post, Toptal Freelance Software Engineer Vilson Duka explains what makes PHP 7 different, and why it’s time to make the switch.

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Dario Bertini
To Python 3 and Back Again: Is It Worth the Switch?

Since its debut in 2008, Python 3 has come a long way. Gone are the days when it lacked support for almost all useful libraries and tools. Python 3 offers many improvements and amazing new features that make writing robust code in Python easier than ever.

In this article, Toptal engineer Dario Bertini discusses some of the improvements and features that Python 3 has to offer, and explains whether switching to Python 3 is a smart choice right now.

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Darion Cassel
Developer's Guide to Improving Project Structure in Meteor Applications

Meteor is a framework for rapidly building real-time JavaScript web applications. It can be used to build complex applications with amazing ease. However, that can often result in adoption of bad development practices and poorly structured code.

In this article, Toptal engineer Darion Cassel shares some simple ways to improve the structure of your next Meteor-based web application without resorting to complicated boilerplates and scaffolding tools.

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Adnan Ademovic
An Introduction to Robot Operating System: The Ultimate Robot Application Framework

Robot Operating System, a framework for building robot applications, allows developers to assemble a complex system by connecting existing solutions for small problems.

In this article, Toptal engineer Adnan Ademovic gives us a step-by-step tutorial to building software for an onboard computer that allows us to remotely control and monitor a robot and running it in a simulated world using Robot OS.

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Bojan Kverh
How to Get Rounded Corner Shapes In C++ Using Bezier Curves and QPainter: A Step by Step Guide

The current trend in graphic design is to use a lot of rounded corners in all sorts of shapes. We can observe this on many web pages, mobile devices, and desktop applications, as rounded corners make the user interface feel smoother and nicer. However, what if we have to generate rounded corners on the fly, and we cannot preload it from an image?

In this article, Toptal Freelance Software Engineer Bojan Kverh guides us in a step-by-step tutorial on how to develop a simple class in C++ that can turn a complex polygon into a shape with rounded corners using Bezier curves and QPainter.

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Andrew Crosio
Service Oriented Architecture with AWS Lambda: A Step-by-Step Tutorial

AWS Lambda offers a relatively thin service with a rich set of ancillary configuration options, making it possible to implement easily scalable and maintainable applications leveraging these services.

In this article, Toptal engineer Andrew Crosio gives us a step-by-step tutorial for building an image uploading and resizing service and demonstrates how AWS Lambda can be used as a platform to easily build service oriented architecture applications.

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Stephen Villee
Persisting Data Across Page Reloads: Cookies, IndexedDB and Everything In-Between

Modern web browsers offer a number of different APIs and mechanisms to storing data on the client-side. But are all of these options created equal?

In this article, Toptal engineer Stephen Villee demystifies the various client-side storage options available in modern web browsers and explains how each of these can play a role in storing session data on the client-side.

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Kate Scheer
Project Rider: A Standalone ReSharper IDE

With Microsoft’s no-brainer shift towards open source and interoperability it was only a matter of time before we started seeing alternatives to some of their key products, like Visual Studio. Enter Project Rider: the code name for IDE guru JetBrains’ competition to Visual Studio.

Here’s the lowdown on Project Rider, the newest member of the IntelliJ platform family.

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José Maldonado
The Art of War Applied To Software Development

The Art of War is an ancient military treatise, but despite its age, the text is still included in the syllabus at many military schools. Sun Tzu’s principles and teachings also have practical applications in politics, business, sports, and, believe it or not, software development. In fact, you might just be applying some of these principles in your daily routine, without even knowing.

In this post, Toptal Freelance Software Engineer Jose F. Maldonado explains why many of these ancient teachings still matter, and what you can do to make them work for you and your team.

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Ivan Rogic
React, Redux and Immutable.js: Ingredients for Efficient Web Applications

Unlike most front-end web frameworks, React’s aim is to solve the various challenges of building user interfaces that rely on changing data. Although React is a simple JavaScript library and is easy to get started with, it is still possible to misuse it in ways that deny the web app from reaping the benefits that React has to offer.

In this article, Toptal engineer Ivan Rogic demonstrates the synergy of React, Redux and Immutable.js, and shows how these libraries together can solve many performance issues that are often encountered in large web applications.

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Andrei Boyanov
Python Design Patterns: For Sleek And Fashionable Code

Python is a powerful, object-based, high-level programming language with dynamic typing and binding. Due to its flexibility and power, developers often employ certain rules, or Python design patterns. What makes them so important and what do does this mean for the average Python developer?

In this post, Toptal Senior Software Engineer Andrei Boyanov explains why Python is great for design patterns, and how they can be used to unlock even more potential, or to streamline development and make code more maintainable.

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Dino Causevic
Tree Kernels: Quantifying Similarity Among Tree-Structured Data

Today, a massive amount of data is available in the form of networks or graphs. For example, the World Wide Web, with its web pages and hyperlinks, social networks, semantic networks, biological networks, citation networks for scientific literature, and so on.

A tree is a special type of graph, and is naturally suited to represent many types of data. The analysis of trees is an important field in computer and data science. In this article, we will look at the analysis of the link structure in trees. In particular, we will focus on tree kernels, a method for comparing tree graphs to each other, allowing us to get quantifiable measurements of their similarities or differences. This an important process for many modern applications such as classification and data analysis.

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Francisco Temudo
How to Set up a Microservices Architecture in Ruby: A Step by Step Guide

Microservices are one of the latest trends in software design. In a microservices architecture, the classic monolithic back-end is substituted by a suite of distributed services. This design allows better separation of responsibilities, easier maintenance, greater flexibility in the choice of technologies for each service, and easier scalability and fault tolerance.

In this article, Toptal Freelance Software Engineer Francisco Temudo guides us in a step-by-step tutorial on how to build a microservices suite using Ruby.

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Radek Ostrowski
How I Used Apache Spark and Docker in a Hackathon to Build a Weather App

Hackathons often inspire engineers to create amazing software. By blending various technologies together, really useful and often fun projects can be realized in a short period of time.

In this article, Toptal engineer Radek Ostrowski shares his experience participating in the IBM Sparkathon, and walks us through how he elegantly combined the power of Apache Spark and Docker in IBM Bluemix to build a weather app.

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Stepan Yakovenko
An Informal Introduction to DOCX

With approximately one billion people using Microsoft Office, the DOCX format is the most popular de facto standard for exchanging document files between offices.

While DOCX is a complex format, you may want to parse it manually for simpler tasks such as indexing, converting to TXT and making other small modifications. I’d like to give you enough information on DOCX internals so you don’t have to reference the ECMA specifications, a massive 5,000 page manual.

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Michele Sciabarra
Developing for the Cloud in the Cloud: BigData Development with Docker in AWS

More and more people are moving their work from desktop applications to the cloud using an equivalent online web application. However, this has unfortunately not been true for software development IDEs. Although there have been some attempts to provide an online IDE, they have not come anywhere close to traditional IDEs.

In this article, Toptal Freelance Software Engineer Michele Sciabarra guides us on how to build a cloud-based development environment for Scala and big data applications, with the help of Docker in Amazon AWS.

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Jeffrey Shumaker
Guide To Budget Friendly Data Mining

Although database programming does not evolve at nearly the same pace as traditional application programming, recent advancements in several fields are bringing new techniques and technologies within the reach of small and independent developers.

In this guide, Toptal Freelance Software Engineer Jeffrey Shumaker explains how developers can quickly and easily tap these methods to identify database issues they may not even be aware of, and how they can build excellent data mining tools without spending a lot on expensive software licenses.

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Peter Goodspeed-Niklaus
Eliminating the Garbage Collector: The RAII Way

Manual memory management is a nightmare that programmers have been inventing ways to avoid since the invention of the compiler. Programming languages with garbage collectors make life easier, but at the cost of performance.

In this article, Toptal engineer Peter Goodspeed-Niklaus gives us a peek into the history of garbage collectors and explains how notions of ownership and borrowing can help eliminate garbage collectors without compromising their safety guarantees.

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Cong Liu
Caching in Spring with EhCache Annotations

EhCache is a widely-used, pure Java cache that can be easily integrated with most popular Java frameworks, such as Spring and Hibernate. It is often considered to be the most convenient choice for Java applications since it can be integrated into projects easily. EhCache Spring Annotations allows seamless integration into any Spring application by simply adding annotations to cacheable methods, without modifying the method implementations. This article focuses on boosting your Spring applications with EhCache Spring Annotations.

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Nermin Hajdarbegovic
Google Cardboard Overview: VR On The Cheap

Google Cardboard was envisioned as the cheapest Virtual Reality (VR) solution on the planet, and at this point, nothing else comes close in terms of pricing. However, the low price did not bring about mass adoption, and Google’s Android-based VR platform is nothing more than a tech curiosity at this point.

In this post, Toptal Technical Editor Nermin Hajdarbegovic leverages his extensive experience in the graphics industry to explain what’s keeping Cardboard VR down, and what the platform needs to attract more users, investment, and development.

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Federico Tomassetti
Creating Usable JVM Languages: An Overview

Java Virtual Machine (JVM), the powerful virtual machine behind programming languages like Java and Scala, provides a platform-independent environment for executing compiled bytecode. Programming languages built for the JVM can be used to write programs that can run on a wide range of platforms without modification and can even leverage all the libraries and frameworks that exist for the JVM.

In this article, Toptal engineer Federico Tomassetti presents an overview of the strategy and various tools involved in creating our very own programming language for the JVM.

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Leandro Lima
WSGI: The Server-Application Interface for Python

Nowadays, almost all Python frameworks use WSGI as a means, if not the only means, to communicate with their web servers. This is how Django, Flask and many other popular frameworks do it.

This article intends to provide the reader with a glimpse into how WSGI works, and allow the reader to build a simple WSGI application or server.

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Vasilii Lapin
True Dependency Injection with Symfony Components

The Dependency Injection Container in Symfony2 allows components to be injected with their dependencies, and is often used as a Service Locator, which when combined with the DI-container pattern is considered to be an anti-pattern by many.

In this article, Toptal engineer Vasilii Lapin shows us how you can build a simple Symfony2 application using the DI-container, but without implementing the Service Locator pattern.

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Josip Medic
Context Validation in Domain-Driven Design

Handling all validation in domain objects results in objects that are huge and complex to work with. In domain-driven design, using decoupled validator components allows your code to be much more reusable and enables validation rules to rapidly grow.

In this article, Toptal engineer Josip Medic shows us how validation can be decoupled from domain objects, made context-specific, and structured well to achieve more sustainable validation code.

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William Coates
What's New in ES6? Perspective of a CoffeeScript Convert

CoffeeScript allows developers to make the most out of JavaScript-based platforms without having to jump through its awkward language hoops. However, with the introduction of ES6 features into major JavaScript engines, plain JavaScript is now nearly as friendly and powerful out-of-the-box as CoffeeScript.

In this article, Toptal engineer William Coates shares his findings on ES6 from the perspective of a CoffeeScript convert.

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Danny Morabito
NodeOS: The JavaScript Based Operating System

An operating system written in Node.js? Yes, it exists, and it’s called NodeOS. Think for a second about the progress Node.js has made in the short time it’s been around. Now, imagine the same thing happening with an operating system.

In this article, Toptal engineer Danny Morabito introduces us to NodeOS, guiding us with a step-by-step tutorial on how to create our first NodeOS application using nothing more than Node.js.

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Stefan Progovac
iOS Animation and Tuning for Efficiency

Smooth animations and flawless transitions are key to perceived performance in modern mobile applications. Without the right tools, tuning iOS animation for efficiency can be a challenge in itself.

In this article, Toptal engineer Stefan Progovac demonstrates the role of Instruments, a sophisticated set of performance profiling tools for iOS, discussing how they can help you understand animation performance bottlenecks and some strategies for working around them.

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Brandon R Johnson
Will Shoppers And Developers Adapt to Proximity Marketing In-Store?

Talking about proximity marketing will get you varying reactions, from concerns about privacy issues to the idea that your phone is going to spam you with annoying ads non-stop, but if you boil down the idea, there are some really compelling concepts here.

When you clear away all the buzzwords, what exactly is this shift we’re seeing? It’s the world customizing itself to you. The world is reacting to your presence, specific to you as an individual. Retailers and start-ups have taken notice, and the concepts of mobile location analytics and proximity marketing are emerging out of that.

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Nermin Hajdarbegovic
Cold War Tech: It’s Still Here, And Still Being Used

The long-term effect of the Cold War on science and technology is more profound than Nena’s 99 Luftbalons, or any Oliver Stone Vietnam flick.

If you are reading this, you’re already using Cold War technology; The Internet. That’s not all. A lot of tech and infrastructure we take for granted was developed, or at least conceived, during these tumultuous decades.

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Richard Forsythe
Demystifying iOS 9 Spotlight Search for Developers

Spotlight search in Apple iOS 9, compared to earlier versions, has been made much more prominent and personal. With suggestions from Siri and integration opportunities for third-party apps, iPhone’s search functionality is no longer limited to the scope of Apple’s own apps. In this article, Toptal engineer Richard Forsythe explores some iOS SDK functionalities that allow apps to make content available to the user via Spotlight search.

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Adel Fayzrakhmanov
Single Responsibility Principle: A Recipe for Great Code

Maintainable code is something we all desire and there are no shortage of coding principles that promise it. It is not always apparent how tremendously useful these principles are during the early stages of development. Nonetheless, the effort put in to ensure these qualities certainly pay off as the project grows and development continues. In this article, Toptal engineer Adel Fayzrakhmanov discusses how the Single Responsibility Principle is one of the most important aspect in writing good maintainable code.

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Nermin Hajdarbegovic
Hosting For Freelance Developers: PaaS, VPS, Cloud, And More

Whether you’re creating a virtual storefront, deploying an app, or simply doing some third-party testing and development, chances are you need some server muscle. The good news is that there is a lot to choose from. The hosting industry may not be loud or exciting, but it never sleeps; it’s a dog eat dog world, with cutthroat pricing, a lot of innovation behind the scenes, and cyclical hardware updates.

In this article, we take a look at hosting options for freelance software engineers: PaaS, Cloud, VPS, dedicated, and more.

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Nazar Hussain
Building a Color-based Image Search Engine in Ruby

With modern image editing tools, we often take for granted the ability to extract or identify color on some part of any image. However, doing it programmatically is not exactly so straightforward. Camalian, a Ruby gem, changes that, making extracting and manipulating colors in an image as easy as possible. In this article, Toptal engineer Nazar Hussain provides some insight into how various color spaces work, introduces Camalian, and gives an overview of how to use it to build a color-based image search engine in Ruby.

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Oguz Gelal
Ultimate Guide to the Processing Language Part I: The Fundamentals

Rapid prototyping and the ability to produce quick visual results are features of many programming languages and frameworks. However, some take it even further by making these their primary goals. Processing, a programming language based on Java, allows its users to code within the context of visual arts and has been designed from the ground up to provide instant visual feedback. In this article, Toptal engineer Oguz Gelal provides a gentle introduction to Processing and some insights into its inner mechanics.

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Nermin Hajdarbegovic
iOS 9 Betas And WatchOS 2 For Developers

Apple’s iOS 9 and WatchOS 2 updates brings a number of novel features, including improved multitasking for iPads and a host of aesthetic tweaks. However, while iOS 9 is just an incremental update with a focus on the new iPad Pro, WatchOS 2 is not a skin-deep update. Apple has changed the WatchOS architecture and opened up a range of new possibilities for developers.

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Mahmud Ridwan
Going Real-Time with Redis Pub/Sub

Real-time applications have already started to dominate the landscape of the Internet. With modern frameworks and standardization of the necessary client-side features, building a real-time web application has become a breeze. However, such web applications still pose unique scalability challenges.

In this article, Toptal engineer Mahmud Ridwan explores the architecture of a simple real-time web application that works using Redis Pub/Sub and doesn’t compromise its horizontal scalability.

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Krzysztof Ożóg
Online Video with Wowza and Amazon Elastic Transcoder

Performance and data interoperability are critical to the success of any web application. For web apps that need to support video processing – which is inherently compute- and I/O-intensive – these challenges are particularly acute. In this post, I describe some of my experience successfully incorporating video capabilities into a PHP-based web app, leveraging open source technologies and cloud-based services to the greatest extent possible.

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Nermin Hajdarbegovic
Slow Android Wear Adoption Is Stifling Development

Several factors conspired to stifle Android Wear growth, ranging from lack of Google development, to inadequate hardware. Some of these problems have been addressed, some are being addressed, while others cannot be addressed with currently available technology.

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Nikola Todorovic
Ruby Metaprogramming Is Even Cooler Than It Sounds

Ruby metaprogramming, one of the most interesting aspects of Ruby, enables the programming language to achieve an extreme level of expressiveness. It is because of this very feature that many gems, such as RSpec and ActiveRecord, can work the way they do. In this article, Toptal engineer Nikola Todorovic demystifies Ruby metaprogramming using some examples that are relevant to everyday programming and aims to bring it closer to average Ruby developers.

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Mahmud Ridwan
Simplified NGINX Load Balancing with Loadcat

NGINX, a sophisticated web server, offers high performance load balancing features, among many other capabilities. Like most other web server software for Unix-based systems, NGINX can be configured easily by writing simple text files. However, there is something interesting about tools that configure other tools, and it may be even easier to configure an NGINX load balancer if there was a tool for it.

In this article, Toptal engineer Mahmud Ridwan demonstrates how easy it is to build a simple tool with a web-based GUI capable of configuring NGINX as a load balancer.

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Stéphane P. Péricat
Electron: Cross-platform Desktop Apps Made Easy

Building cross-platform desktop applications has been something of a nightmare for a very long time, as extreme differences between popular desktop operating systems makes it a challenging feat. However, in light of newer tools and frameworks like Electron, building a cross-platform desktop application has never been easier. In this article, Toptal engineer Stéphane P. Péricat walks us through a step-by-step tutorial to building a cross-platform password key-ring desktop application using technologies that most of us are already familiar with.

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Anna Chiara Bellini
Open Source: It's Not That Scary!

Is open source scary? Do developers think that nobody would be interested in their personal projects? What are the fears associated with publishing your own work for the public to see? In this article, Toptal Director of Engineering Anna Chiara Bellini shares how, as an accomplished engineer, she made her first contribution to GitHub. This guide features all the step-by-step basics to getting involved in open source, including everything from what open source software is, to how to start working with Git and GitHub, to actually making meaningful contributions to open source projects.

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Carlos Ramirez III
How to Use Rails Helpers: A Bootstrap Carousel Demonstration

One of the most misused, misunderstood, and neglected of all the Rails built-in structures is the view helper. Helpers often get a bad reputation for being a dumping ground for one-off methods used across the entire application’s view layer. But what if your helpers could be more semantic, better organized, and even reusable across projects? What if they could be more than just one-off functions sprinkled throughout the view, but powerful methods that generated complex markup with ease leaving your views free of conditional logic and code?

Let’s see how to do this when building an image carousel, with the familiar Twitter Bootstrap framework and some good old-fashioned object-oriented programming.

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Arminas Zukauskas
Building REST API for Legacy PHP Projects

Every once in a while PHP developers are charged with tasks that require them to extend the functionalities of legacy projects, a task that often includes building REST APIs. Building a REST API for PHP-based projects is challenging, but in the absence of proper frameworks and tools, it can also be a particularly difficult goal to get right. In this article, Toptal engineer Arminas Zukauskas shares his advice, with sample code, on how to build a modern structured REST API around existing legacy PHP projects.

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Juan Pablo Scida
Hunting and Analyzing High CPU Usage in .NET Applications

Software performance in production is hard to analyze. Things can go wrong at any time, and code can start executing in ways that weren’t planned for. In these cases, what do we do? In this article, Toptal engineer Juan Pablo Scida analyzes a real scenario of high CPU usage of a web application. He covers all the processes and .NET code analysis involved to identify the problem, explains how the problem was solved, and most importantly, explores why this problem happened in the first place.

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Daniel Angel Muñoz Trejo
Optimized Successive Mean Quantization Transform

Image processing algorithms are often very resource intensive due to fact that they process pixels on an image one at a time and often requires multiple passes. Successive Mean Quantization Transform (SMQT) is one such resource intensive algorithm that can process images taken in low-light conditions and reveal details from dark regions of the image.

In this article, Toptal engineer Daniel Angel Munoz Trejo gives us some insight into how the SMQT algorithm works and walks us through a clever optimization technique to make the algorithm a viable option for handheld devices.

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Alvaro Oliveira
Skype Tips for Remote Teams

Toptal has a strong remote culture), to say the least. To keep up with each other, we need a tool to keep team members in sync, where we can reach any other person at a moment’s notice. We use Skype as our main communication channel among Toptal’s core team.

Over the years, Skype has grown a lot, and has become a versatile tool that can be used on all of your devices at once, syncing chat amongst them, and providing a simple way to call and share screens. It is a tool that we leverage every day for our internal operations.

As heavy Skype users, there are a few things we’ve noticed that might not be clear to everyone. Here are a few tips on how you and your remote team can get the most of of Skype.

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Nick McCrea
Learn to Code: Wisdom and Tools for the Journey

It’s no surprise that more and more people, from all kinds of backgrounds, are deciding to learn to code. But, each person who tackles the task is soon faced with an unpleasant reality: Learning to program is hard. Contrary to expectations, the feeling of “I don’t get it,” may persist unabated long into the journey, making once bright-eyed beginners feel hopeless, lost, and ready to give up.

The moral of the story is this: Be prepared. The path to programmer paradise is a long one, and without the right mindset at the beginning, it can quickly lose its appeal. In this article, I’ll attempt to give you some guidance on what to expect on your journey, how best to go about it, and what tools and resources you may find helpful along the way.

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Nermin Hajdarbegovic
What Does Force Touch Mean For UI And UX?

Force Touch is not a new idea. BlackBerry experimented with the concept back in 2008, and a few Android phone makers also examined the possibility of using Force Touch on their products. In fact, Force Touch support has been a part of Android for years; it was introduced in Android 1.0.

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Lijana Saniukaite
Speeding up Application Development with Bootstrap

Bootstrap, one of the most used HTML/CSS/JavaScript front-end frameworks, offers a little more than just fancy customizable user interface elements. It provides a great starting point for many types of projects, a plethora of components, and many nifty styles predefined for responsive layout and utility classes to help keep your HTML and CSS code clean.

In this article, Toptal designer Lijana Saniukaite walks us through some practical Bootstrap tips and best practices to speed up your application development.

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Vladyslav Millier
Debugging Memory Leaks in Node.js Applications

Memory leaks in long running Node.js applications are like ticking time bombs that, if left unchecked in production environments, can result in devastating outcomes. These bugs are often considered to be hard to find. However, with the right tools and a strategic approach, memory leaks can not only be solved but also avoided in the future. In this article, Toptal engineer Vladyslav Millier gives us insight into what memory leaks are, how some sophisticated debugging tools can be used to find memory leaks, and how to plug them once and for all.

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Breanden Beneschott
Is Open Source Open to Women?

The fact that women are underrepresented in tech is nothing new. However, while we’ve seen the gender diversity reports from companies like Google, Facebook, and many more, a look at the number of women in the open source community suggests that the numbers might be worse than these reports imply. In this post, Toptal COO Breanden Beneschott shares the results of a study looking at gender on GitHub and considers a few reasons why GitHub is so male-dominated, including a few ideas on how we can make the open source community a more welcoming place.

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Alberto Mancini
The GWT Toolkit: Build Powerful JavaScript Front Ends Using Java

The GWT Web Toolkit, formerly known as Google Web Toolkit, is a set of development tools for building and optimizing complex browser-based applications using the Java programming language. What makes GWT not “yet another Java tool to write web apps,” is the fact that the heart of the toolkit is a compiler that converts Java into JavaScript, enabling developers to write front-end web applications while leveraging all of Java’s strengths.

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David Marín
Developer’s Guide to Open Source Licenses

Many developers often overlook, or do not thoroughly think through the implications of open source licenses. Whether you’re planning to open source your own project under one of these licenses, or you intend to integrate some other open source project into one of your own, it’s important to have at least some knowledge of what these licenses are, how they may affect your projects, and how they complement or contradict one another. In this article, Toptal engineer David Marín gives us a comprehensive guide to some of the most popular open source licenses, and several rules of thumb to follow when choosing a license for future open source projects.

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Rob Moore
Towards Updatable D3.js Charts

When Mike Bostock created D3.js, he introduced a tried and true reusable charts pattern for implementing the same chart in any number of selections. However, the limitations of this pattern are realized once the chart is initialized. In this article, Toptal engineer Rob Moore presents a revised reusable charts pattern that leverages the full power of D3.js.

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Nermin Hajdarbegovic
Apple Pay And Android Pay For Developers

Today, we will be taking a look at the future of mobile payments and emerging opportunities for developers. Needless to say, with each new opportunity, developers will have to face new challenges.

However, since we are talking about money, I don’t think anyone expects a shortage of software developers eager to learn a few new tricks and get into this space.

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Igor Delac
Implementing a Remote Framebuffer Server in Java

Connecting to remote computers and working on them through terminals over a network is something we often take for granted. Technologies that enable us to do this have changed the way we work and have opened doors to amazing possibilities. Although the inner workings of these technologies may seem like obscure knowledge, implementations of many of these technologies are surprisingly straightforward. In this article, Toptal engineer Igor Delac gives us a step-by-step tutorial on how to implement the Remote Framebuffer server-side protocol in Java, allowing Swing-based applications to run and be interacted with remotely using standard VNC clients.

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Matias Hernandez
Sass Style Guide: A Sass Tutorial on How to Write Better CSS Code

When working on big web applications as a team with other developers, code needs to be scalable and readable. This can be a challenging process when it comes to CSS, although preprocessors like Sass are available. But only using preprocessors will only get you so far. In this article, Toptal engineer Matias Hernandez presents a style guide with advice on how to improve the way you write your code.

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Pablo Villoslada Puigcerber
How to Turn Your Raspberry Pi Into a Development Server

The Raspberry Pi is a little computer that you can get for as low as US $35 and on which you can run many different types of software and build many different projects. In this article, I’m going to guide you through the process of setting it up as a home development server and deploying a full-stack JavaScript application that you can access from outside your network. This is great for setting up your own remote digital workspace, or simply to have control over the hardware you use for development.

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Dejan Zivanovic
Test Automation in Selenium Using Page Object Model and Page Factory

Proper test automation is not always easy to achieve and requires almost as much design and thought as needed for the software itself. In the agile way of development tests are an essential ingredient in ensuring quality of software. However, unless these test codes are maintainable, they can prove to be more of a nuisance, especially when it comes to automated testing of modern web applications. This article is an easy introduction to Selenium features Page Object and Page Factory, how they can be used to model web applications, and how to write maintainable test code using them.

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Mahmud Ridwan
Taming WebRTC with PeerJS: Making a Simple P2P Web Game

WebRTC has opened doors to all kinds of new peer-to-peer web applications and games that can run in the browser without the need of additional plugins. However, being a relatively new technology, it still poses some unique challenges to developers. PeerJS aims to tackle some of those challenges by providing an elegant API and insulating developers from WebRTC’s implementation differences. In this article, Toptal engineer Mahmud Ridwan provides an introductory tutorial to building a simple, peer-to-peer web game using PeerJS.

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Nermin Hajdarbegovic
A Brief Overview Of Vulkan API

Here’s the Vulkan API in a hundred words or less: It’s a low-overhead, close-to-metal API for 3D graphics and compute applications. Vulkan is basically a follow-on to OpenGL. It was originally referred to as the “next generation OpenGL initiative,” and it includes a few bits and pieces from AMD’s Mantle API. Vulkan is supposed to provide numerous advantages over other GPU APIs, enabling superior cross-platform support, better support for multithreaded processors, lower CPU load, and a pinch of OS agnosticism.

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Nermin Hajdarbegovic
Toptal's List Of Top Free Programming Books

The Internet is mankind’s biggest repository of knowledge, information, useful (and useless: think of cat pics) digital content. Today, we will be taking a quick look at something useful and down to earth: free online programming books.

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Eduard Grinchenko
Why You Need to Upgrade to Java 8 Already

The newest version of the Java platform, Java 8, was released more than a year ago. Many companies and developers are still starting new applications with old versions of Java. There are very few good reasons to do this, because Java 8 has brought some important improvements to the language. I’ll show you a handful of the most useful and interesting ones.

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Radek Ostrowski
Getting Started with Docker: Simplifying Devops

Docker, an open source tool, has changed the way we think about deploying applications to servers. By leveraging some amazing resource isolation features of the Linux kernel, Docker makes it possible to easily isolate server applications into containers, control resource allocation, and design simpler deployment pipelines. Moreover, Docker enables all of this without the additional overhead of full-fledged virtual machines.

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Stefan Varga
Building an MVC Application with Spring Framework: A Beginner's Tutorial

The Spring Framework is a powerful, feature-rich, and well-designed framework for the Java platform. It offers a collection of programming and configuration models that aim to simplify and streamline the development process of robust and testable applications in Java. In this article, Toptal engineer Stefan Varga challenges the popular notion of Java as a complicated platform for simple needs, and walks us through a step by step tutorial to building a simple MVC application with the Spring Framework and JPA.

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Johannes Stein
Cold Dive into React Native: A Beginner's Tutorial

The development of cross-platform mobile applications has always been a source of many challenges. Although tools like Apache Cordova and Haxe do solve some of the associated issues, they are still not the ideal solution in many cases. React Native changes that by providing the power of React.js for mobile platforms and a promise of consistent developer experience across multiple platforms.

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Marcin Kmiec
Simplifying RESTful API Use and Data Persistence on iOS with Mantle and Realm

A large number of modern mobile applications interact with web services in one way or another, and iOS applications are no different. Mantle (a model framework) and Realm (a mobile database) come with the promise of simplifying some of the hurdles in consuming web services through RESTful APIs and persisting data locally. In this article, Toptal engineer Marcin Kmiec shows how to build a simple iOS application using Mantle and Realm and demonstrates how this approach helps to eliminate a large amount of boilerplate code.

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Asa Kaplan
OpenGL Tutorial for Android: Building A Mandelbrot Set Generator

OpenGL, a cross-platform API for rendering 2D and 3D graphics, is extremely powerful and yet surprisingly easy to get started with. Although one may find the most common applications of OpenGL and rendered graphics in video games only, in reality there are far more uses. To demonstrate the power of OpenGL, we’ll be building a Mandelbrot set generator on Android using OpenGL ES.

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Nermin Hajdarbegovic
Google Cloud Source Repositories vs. Bitbucket vs. GitHub: A Worthy Alternative?

Google’s new cloud code platform does not appear to be taking on GitHub head on. Instead, Cloud Source Repositories (CSR) will allow users to connect to repositories hosted on GitHub or Bitbucket. However, everything is automatically synced to the Google Cloud Source Repository.

The good news is that a Google CSR can be connected to another Git repository hosted on GitHub or Bitbucket. All changes will be synchronised on both platforms, as you can set Google CSR to automatically mirror from GitHub and Bitbucket.

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Eugene Tsygankov
Eight Reasons Why Microsoft Stack Is Still a Viable Choice

In today’s world where there are a lot of choices for writing quality software, it’s easy to overlook some tools that are viable options in developing modern software. These software development tools, in competition with each other, often fluctuate in popularity and developer preferences. Many excellent tools are viable options for any given project. This article provides eight reason in favor of the Microsoft stack and why it is still a reasonable choice for software development today.

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Nermin Hajdarbegovic
Case Study: Using Toptal To Reel In Big Fish

Whether you’re an avid angler or an app developer, you may be interested in taking a closer look at the development of a fishing app, which involved some of your fellow Toptalers.

The goal was to create an app that would be truly useful in a professional fishing setting, while at the same time meeting a hard deadline. Since Fatsack Outdoors wanted to launch the app at one of the biggest fishing tradeshows of the year, the deadline was non-negotiable.

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Altaibayar Tseveenbayar
OpenCV Tutorial: Real-time Object Detection Using MSER in iOS

Detecting objects of interest in images has always been an interesting challenge in the realm of computer vision, and many approaches have been developed over recent years. As mobile platforms are becoming increasingly powerful, now is the perfect opportunity to develop interesting mobile applications that take advantages of these algorithms. This article walks us through the process of building a simple iOS application for detecting objects in images.

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Sigfried Gold
Ultimate In-memory Data Collection Manipulation with Supergroup.js

In-memory data collection manipulation is something that we often need to do in data-centric reporting and visualization applications. When needed, we often tend to resort to complex loops, list comprehensions, and other suboptimal means, which can easily end up being a huge mess of hard-to-maintain spaghetti code. Supergroup.js is an in-memory data manipulation library that can be used to solve some common data manipulation challenges on limited datasets.

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Eugene Mirotin
Ractive.js - Web Apps Made Easy

Ractive.js provides powerful capabilities for web app development in a way that is refreshingly simple to learn and use. In this article, Toptal Engineer Eugene Mirotin walks you through the process of building a simple Ractive search app, demonstrating some of Ractive’s key features and the ways in which it helps simplify web app development. Code samples are provided and explained.

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Sripal Reddy Vindyala
How to Tune Microsoft SQL Server for Performance

To retain its users, any application or website must run fast. For mission critical environments, a couple of milliseconds delay in getting information might create big problems. As database sizes grow day by day, we need to fetch data as fast as possible, and write the data back into the database as fast as possible. To make sure all operations are executing smoothly, we have to tune Microsoft SQL Server for performance.

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Tomas Holas
Navigating the React.JS Ecosystem

In this article, I’ll go through some of the interesting features and libraries that are available to use with React. Even if you don’t plan on using React, taking a look at its ecosystem is inspiring. You may want to simplify your build system using the powerful, yet comparatively easy to configure, module bundler Webpack, or start writing ECMAScript 6 and even ECMAScript 7 today with the Babel compiler. So, let’s explore the React ecosystem!

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Sergey Kolodiy
Unit Tests, How to Write Testable Code and Why it Matters

In this article, I will show that unit testing itself is quite easy; the real problems that complicate unit testing, and introduce expensive complexity, are a result of poorly-designed, untestable code. We will discuss what makes code hard to test, which anti-patterns and bad practices we should avoid to improve testability, and what other benefits we can achieve by writing testable code. We will see that writing testable code is not just about making testing less troublesome, but about making the code itself more robust, and easier to maintain.

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Paul Barnes
The Ultimate Introduction To Agile Project Management

Simply calling something Agile isn’t particularly helpful. The word, even in a software context, means different things to different people or organizations. There are many facets, definitions, implementations, and interpretations.

In this article, Toptal Head of Projects Paul Barnes teaches about behaviors, frameworks, techniques, and concepts supporting agile project management in software development.

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Jovan Jovanovic
Let LoopBack Do It: A Walkthrough of the Node API Framework You've Been Dreaming Of

While Ruby has Rails and Python has Django, the dominant application development framework for Node has yet to be established. But, there is a powerful contender gaining steam: LoopBack, an open source API framework built by StrongLoop, the creators of Express.

Let’s take a closer look at LoopBack and it’s capabilities by turning everything into practice and building an example application.

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Nermin Hajdarbegovic
Android M (Android 6.0) For Developers: An Evolutionary Step In The Right Direction

Google announced Android M at its annual I/O dev conference in late May, and the new OS is coming to our beloved Android devices later this year. Android 6.0 is more of an evolutionary step, whereas Android 5.0 was a big leap forward thanks to its 64-bit ART runtime and all new Material Design.

However, Android M should not be dismissed as a minor update. In this post, I will try to explain why.

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Tomislav Bacinger
The 10 Most Common Bootstrap Mistakes That Developers Make

Bootstrap is a powerful toolkit. It comes bundled with basic HTML and CSS design templates that include many common UI components. Most of the important pitfalls are mentioned in the Bootstrap documentation, but still some mistakes are pretty subtle, or have ambiguous causes. This article outlines some of the most common mistakes, problems, and misconceptions when using Bootstrap.

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Tomislav Bacinger
What is Bootstrap? A Short Bootstrap Tutorial on the What, Why, and How

If you’re doing anything web related, chances are you’ve heard about Bootstrap. Bootstrap is a powerful toolkit - a collection of HTML, CSS, and JavaScript tools for creating and building web pages and web applications. It is a free and open source project, hosted on GitHub, and originally created by (and for) Twitter. If by now you still don’t know what Bootstrap is, or you just want to get a better overview of what it is and what it does best, you’ve come to the right place.

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Nermin Hajdarbegovic
Brace Yourselves Android Developers, A New Android Compiler Is Coming

With Dalvik out of the picture, many people expected Google’s new 64-bit capable ART runtime to stick around for years, which it probably will, but it will get a major overhaul in the near future. In addition to offering support for 64-bit hardware, ART also introduced ahead-of-time (AOT) compilation, while Dalvik was a just-in-time (JIT) compiler.

Throw in new 10-core ARM processors and Intel mobile processors based on three different architectures, and you end up with spicy, Google-style hardware gumbo.

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Mahmud Ridwan
Deploy Web Applications Automatically Using GitHub Webhooks

Deploying instances of a web application to one or more servers manually can often be a monotonous process, and take up a significant amount of your time. With little effort, it is possible to automate the process of deploying your web application with almost zero human intervention. This article outlines a simple approach to automating web application deployments using GitHub webhooks, buildpacks, and Procfiles.

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Nilson Souto
Video Game Physics Tutorial - Part III: Constrained Rigid Body Simulation

In Part I of this three-part series, we saw how the free motion of rigid bodies can be simulated. In Part II, we saw how to make bodies aware of each other through collision and proximity tests. Up to this point, however, we still have not seen how to make objects truly interact with each other. The final step to simulating realistic, solid objects, is to apply constraints, defining restrictions on the motion of rigid bodies.

In this article, we’ll discuss equality constraints and inequality constraints. We’ll describe them first in terms of a force-based approach, where corrective forces are computed, and then in terms of an impulse-based approach, where corrective velocities are computed instead. Finally, we’ll go over some clever tricks to eliminate unnecessary work and speed up computation.

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Elder Santos
Data Mining for Predictive Social Network Analysis

Analysts have come to recognize social network data as a virtual treasure trove of information for sensing public opinion trends and groundswells of support. In this article, Toptal Engineer Elder Santos describes the techniques he employed for a proof-of-concept that effectively analyzed Twitter Trend Topics to predict, as a sample test case, regional voting patterns in the 2014 Brazilian presidential election.

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Advanced Tactics for Highly Collaborative, Remote Teams

Any time you’re physically out of the office or working with someone who isn’t next to you, you’re working remotely. At Toptal, working remotely is a productive and efficient reality that we evangelize to our clients, while practicing what we preach.

In this article, Toptal COO Breanden Beneschott shares great tactics in operating highly collaborative remote teams.

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Ilya Sanosyan
Getting the Most Out of Your PHP Log Files: A Practical Guide

Log files may very well be one of the most underestimated and underutilized tools at a developer’s disposal. Beyond their value for debugging, with a bit of creativity and forethought, logs files can be leveraged to serve as a valuable source of usage information and analytics. In this article, In this article, Toptal engineer Ilya Sanosyan provides a practical guide to maximizing the value we get from our logs.

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Nermin Hajdarbegovic
Windows 10 Development: Addressing Old Problems And Opening New Doors For Developers

Windows 10 represents a departure from Microsoft’s traditional OS strategy. It’s not just a new operating system, it’s an automatic and free update for millions of Windows 8.1 devices. It’s also designed to address a number of user complaints related to the Windows 8.x UI. The changes aren’t just skin deep, as Windows 10 is not a mere redesign with a new UI and fancier apps; it might even mark the start of a new era for Microsoft, and in this post I will explain why.

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Ivan Matec
Azure Tutorial: Predicting Gas Prices Using Azure Machine Learning Studio

Machine learning has changed the way we deal with data. Data driven problems, that are difficult to solve using standard methods, can often be tackled with much more ease using machine learning algorithms. In this article, we will explore Azure Machine Learning features and capabilities through solving one of the problems that we face in our everyday lives.

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Nermin Hajdarbegovic
Android TV Development – Big Screens Are Coming, Get Ready!

Google wants to bring Android to everything from phones and watches, to cars and smart television sets. Unlike Google TV, Android TV is much closer to standard Android. It runs Android 5.0 (at least in the initial launch version) and can be used on new TVs, as well as on standalone devices.

Android TV is not just about improving the way people consume TV content, it’s more about changing the way they do it.

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Avinash Kaza
Business Intelligence Platform: Tutorial Using MongoDB Aggregation Pipeline

In today’s data driven world, researches are busy answering interesting questions by churning through huge volumes of data. Some obvious challenges they face are due the sheer size of dataset that they have to deal with. In this article, we take a peek at a simple business intelligence platform implemented on top of the MongoDB Aggregation Pipeline.

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Nermin Hajdarbegovic
Smartwatch Development: Are Smartwatches Worth The Trouble?

While the Apple Watch is on track to be a commercial success for Apple and its shareholders, technologists are still not entirely convinced smartwatches have what it takes to conquer the market, at least not yet.

What does this mean for developers? What are the implications for other smartwatch platforms and companies behind them?

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Doug Sparling
Full Text Search of Dialogues with Apache Lucene: A Tutorial

Apache Lucene is a powerful Java library used for implementing full-text search on a corpus of text. With its wide array of configuration options and customizability, it is possible to tune Apache Lucene specifically to the corpus at hand - improving both search quality and query capability.

This article gives us a glimpse of the simplicity and ease of customization of the Apache Lucene analysis pipeline.

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Marija Efremova
A Tutorial on iOS 8 App Extensions

iOS 8 introduced a new concept called App Extensions. This new feature did not break down the walls between the applications, but it opened a few doors providing gentle yet tangible contact between some apps. The latest update gave us an option to customize the iOS ecosystem, and we are eager to see this path opening up as well.

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Anton Shkuratov
SVG Text Tutorial: Text Annotation on the Web

Texts are an integral part of user interfaces. In many cases, text annotation plays a vital role in grabbing the user’s attention or allowing the user to decorate and highlight the content they produce.

In this article, we walk through the ins and outs of an open source JavaScript library built for annotating texts on the web.

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Nermin Hajdarbegovic
Toptal’s Selection Of Best Developer Blogs

You are what you read – and most Toptal members and blog subscribers are software developers. So what do you read? Where do professional developers get the latest information about how their peers work and think?

Today, we will be taking a look at a small selection of popular developer blogs frequented by Toptal developers. We’re counting on you (our readers) to expand the list in the comment section.

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Nermin Hajdarbegović
Biometric Security – The Key To Passwordless Authentication Or A Fad?

Passwordless authentication has been the Holy Grail of security for years, but progress has been painfully slow. Until a few years ago, the technology to implement passwordless logins on a grand scale simply wasn’t available.

However, the industry juggernaut is slowly but surely changing this. There are a few technical, legal and even ethical considerations to take into account, but be as it may, biometric, passwordless authentication is here to stay.

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Storm Farrell
Learn Markdown: The Writing Tool for Software Developers

Face it, you’re a software engineer, not a graphic designer. When you need to write a manual, technical document, or report, you just want to write it and be done with it. Especially for you as a software engineer – who is not put off by needing to learn and use some basic syntax conventions – Markdown can be the path of least resistance between what you want to write and getting it written.

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Bret J. Stancil
What To Look Out For In Software Development NDAs

You might presume that Non-Disclosure Agreements (NDAs) have been widely accepted in the tech world as a means to protect sensitive and potentially valuable information from theft and abuse. Not so fast.

Jones Day Corporate Associate Bret J. Stancil examines software developer NDAs for Toptal blog followers in a must-read post for anyone faced with the prospect of signing an NDA.

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Radek Ostrowski
Introduction to Apache Spark with Examples and Use Cases

In this post, Toptal engineer Radek Ostrowski introduces Apache Spark – fast, easy-to-use, and flexible big data processing. Billed as offering “lightning fast cluster computing”, the Spark technology stack incorporates a comprehensive set of capabilities, including SparkSQL, Spark Streaming, MLlib (for machine learning), and GraphX. Spark may very well be the “child prodigy of big data”, rapidly gaining a dominant position in the complex world of big data processing.

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Tino Tkalec
JSON Web Token Tutorial: An Example in Laravel and AngularJS

Authentication is one of the most important parts of any web application. For decades, cookies and server-based authentication was the easiest solution. However, handling authentication in modern Mobile and Single Page Applications can be tricky and demand a better approach. One of the best known solutions to authentication problems for APIs is the JSON Web Token (JWT).

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Amaury Andres Peniche Gonzalez
Meet Volt, A Promising Ruby Framework For Dynamic Applications

In an attempt to make web applications a lot more dynamic, front-end Javascript frameworks like Angular.js, Backbone.js and Ember.js have gained a lot of popularity. However, these frameworks often require a back-end application to be useful, so they are used in conjunction with web frameworks like Ruby on Rails and Django.

On the other hand, Volt is capable of managing the back-end and a dynamic front-end; since both functionalities are tightly integrated into its core.

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Nermin Hajdarbegovic
Nvidia Shield - A Different Take On Android Gaming Consoles

Describing Nvidia Shield as a mere Android console would not do it justice. The console relies heavily on streaming and cloud computing, so it shouldn’t not be viewed as another standalone device.

Nvidia sees Shield as Netflix for games, as a comprehensive Gaming-as-a-Service (GaaS) platform. While it’s still part of the Android ecosystem, Shield could be bad news for some Android game developers, but it also creates a range of new and exciting opportunities.

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Pavel Tiunov
Application Development with Rapid Application Development Framework AllcountJS

AllcountJS is an emerging open source framework built with rapid application development in mind. It is based on the idea of declarative application development using JSON-like configuration code that describes the structure and behavior of the application.

In this article, we walk through a step-by-step tutorial for prototyping a data oriented web application using AllcountJS.

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Nermin Hajdarbegovic
Are We Creating An Insecure Internet of Things (IoT)? Security Challenges and Concerns

After a couple of years of bullish forecasts and big promises, security seems to be the biggest IoT concern. The first few weeks of 2015 were not kind to this emerging industry, and most of the negative press revolved around security.

Was it justified? Was it just “fear, uncertainty and doubt” (FUD), brought about by years of hype? It was bit of both; although some issues may have been overblown, the problems are very real, indeed.

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Nilson Souto
Video Game Physics Tutorial - Part II: Collision Detection for Solid Objects

In Part I of this three-part series on game physics, we explored rigid bodies and their motions. In that discussion, however, objects did not interact with each other. Without some additional work, the simulated rigid bodies can go right through each other.

In Part II, we will cover the collision detection step, which consists of finding pairs of bodies that are colliding among a possibly large number of bodies scattered around a 2D or 3D world.

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Philip R Brenan
Best Programming Editors? A Never Ending Battle With No Clear Winner

Since programmers spend so much time using their favorite editor, they become extremely good at it, and are reluctant to learn to use any other. Even if offered a better editor for some specific task, the skilled programmer can get their existing editor to do the task just well enough, and therefore sees no need to learn how to use a new one.

This is what compelled me to try out a number of different editors and make the transition as easy as possible; I hope my experience saves you time and effort if you find yourself in the same situation.

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Senad Biser
How Not To Manage Your Remote Team of Developers

When entering the remote developers’ world, the biggest obstacle that managers must overcome is to change their mindset by accepting that the developer will not be in plain sight, and where they can manage and follow the work being done.

This new paradigm requires businesses to implement a number of mechanisms to track progress and avoid a redundant workload. Such mechanisms will help both manager and developer be more productive, which is in everyone’s best interest.

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Tomislav Bacinger
Survey of the Best Online Mapping Tools for Web Developers: The Roadmap to Roadmaps

Making your own maps is not a big undertaking anymore, but for developers not familiar with web mapping, the agony of choice might be intimidating. You want to make maps, but don’t know where to start nor which tools to use. I am here to help.

Here, I’ll discuss several of the best available tools, providing a brief overview of each, along with code examples, and weighing the pros and cons.

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Filip Petkovski
Apache Cordova Tutorial: Developing Mobile Applications with Cordova

Mobile applications are creeping in. Developing for each mobile platform can be an exhaustive task, especially if resources are limited. This is where Apache Cordova comes in handy by providing a way to develop mobile applications using standard web technologies - HTML5, CSS3 and JavaScript. This article explores how one can get started with Apache Cordova and build mobile applications targeted at a wide range of mobile devices.

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Mikhail Selivanov
Buggy Java Code: The Top 10 Most Common Mistakes That Java Developers Make

Java, a sophisticated programming language, has been dominating a number of ecosystems for quite a while. Portability, automated garbage collection, and its gentle learning curve are some of the things that make it a great choice in software development. However, like any other programming language, it is still susceptible to developer mistakes.

This article explores the top 10 common mistakes Java developers make and some ways of avoiding them.

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Oleksii Rytov
Why I Decided To Embrace Laravel

Laravel designers didn’t spend too much time reinventing the wheel. A lot of solutions and practices are transferred from other frameworks.

The decision to embrace a new PHP framework should not be taken lightly, so let’s examine why considering Laravel may be worth your time and effort. Toptal freelance software engineer Alex Rytov explains what made him take the plunge and why he believes Laravel has a bright future.

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Ivan Voras
Installing Django on IIS: A Step-by-Step Tutorial

Although the most wide-spread and supported way of running Django is on a Linux system (e.g., with uwsgi and nginx), it actually doesn’t take much work to get it to run on IIS. In this article, Toptal Engineer Ivan Voras walks you through a step-by-step tutorial, clearly explaining how to install Django on IIS.

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Mahmud Ridwan
Predicting Likes: Inside A Simple Recommendation Engine's Algorithms

The Internet is becoming “smarter” every day. The video-sharing website that you frequently visit seems to know exactly what you will like, even before you have seen it. The online shopping cart holding your items almost magically figures out the one thing that you may have missed or intended to add before checking out. It’s as if these web services are reading your mind - or are they?

Turns out, predicting a user’s likes involves more math than magic. In this article we will explore one of the many ways of building a recommendation engine that is both simple to implement and understand.

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Alberto Mancini
How GWT Unlocks Augmented Reality in Your Browser

In our previous post on the GWT Web Toolkit, we discussed the strengths and characteristics of GWT, to mix Java and JavaScript libraries seamlessly in the browser. In today’s post, we would like to go a little deeper, and see the GWT Toolkit in action. We’ll demonstrate how we can take advantage of GWT to build a peculiar application: an augmented reality web application that runs in real time, fully in JavaScript, in the browser. We’ll focus on how GWT gives us the ability to interact easily with many JavaScript APIs, such as WebRTC and WebGL, and allows us to harness a large Java library, NyARToolkit, never intended to be used in the browser.

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Jovan Jovanovic
Shazam It! Music Recognition Algorithms, Fingerprinting, and Processing

You hear a familiar song in the club or the restaurant. You listened to this song a thousand times long ago, and the sentimentality of the song really touches your heart. You desperately want to heart it tomorrow, but you can’t remember its name! Fortunately, in our amazing futuristic world, you have a phone with music recognition software installed, and you are saved.

But how does this really work? Shazam’s algorithm was revealed to world in 2003. In this article we’ll go over the fundamentals of that algorithm.

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Stéphane P. Péricat
MIDI Tutorial: Creating Browser-Based Audio Applications Controlled by MIDI Hardware

Modern web browsers provide a rich set of APIs; some of which have been around for a long time, and have since been used to build powerful web applications.

Web Audio API has been popular among HTML5 game developers, however, the Web MIDI API and its capabilities have yet to be utilized. In this article, Toptal engineer Stéphane P. Péricat guides you through the basics of the Web MIDI API, and shows you how to build a simple monosynth to play with your favorite MIDI device.

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Ahmed Al-Amir
Needle in a Haystack: A Nifty Large-Scale Text Search Algorithm Tutorial

When coming across the term “text search”, one usually thinks of a large body of text, which is indexed in a way that makes it possible to quickly look up one or more search terms when they are entered by a user. This is a classic problem in computer science, to which many solutions exist.

But how about a reverse scenario? What if what’s available for indexing beforehand is a group of search phrases, and only at runtime is a large body of text presented for searching?

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Avinash Kaza
Making an HTML5 Canvas Based Game: A Tutorial Using AngularJS and CreateJS

There are many programming platforms used to develop games, and there are a plethora of devices to play them on, but when it comes to playing games in a web browser, Flash-based development still leads the way.

What if we could port these games to HTML5 Canvas technology and play them on mobile browsers as well? In this article, Toptal engineer Avinash Kaza gave a solution to this.

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Nilson Souto
Video Game Physics Tutorial - Part I: An Introduction to Rigid Body Dynamics

Simulating physics in video games is very common, since most games are inspired by things we have in the real world. Rigid body dynamics – the movement and interaction of solid, inflexible objects – is by far the most popular kind of effect simulated in games.

In this series, rigid body simulation will be explored, starting with simple rigid body motion in this article, and then covering interactions among bodies through collisions and constraints in the following installments.

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Lê Anh Quân
Advanced Java Class Tutorial: A Guide to Class Reloading

In Java development, a typical workflow involves restarting the server with every class change, and no one complains about it. But is Java class reloading that difficult to achieve? And could that problem be both challenging and exciting to solve? In this article, I will try to address the problem, help you gain all the benefits of on-the-fly class reloading, and boost your productivity immensely.

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Nikolay Derkach
A Tutorial for Reverse Engineering Your Software's Private API: Hacking Your Couch

Reverse engineering and hacking are usually related to malicious activities that result in sleepless nights of engineers responsible for system maintenance.

Reverse engineering is a tool that we can utilize to find the flaws and improve our software in many aspects. This article shows us how to use these techniques to learn more about different implementations of web API.

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Leonardo Andrés Garcia Crespo
React.js View State Management Tutorial

One of the biggest and most common problems in front-end web development is state management. A developer is constantly focused on keeping the state object in sync with its view and the DOM representation. Users can interact with the application in many ways and it’s a big task to provide a clean transition from one view state to another.

We will see how using React JavaScript library can help us reduce application complexity and offload UI transitions from our application.

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Ahmed AbdelRazzak
The Publish-Subscribe Pattern on Rails: An Implementation Tutorial

The publish-subscribe pattern] (or pub/sub, for short) is a messaging pattern where senders of messages (publishers), do not program the messages to be sent directly to specific receivers (subscribers). Instead, the programmer “publishes” messages (events), without any knowledge of any subscribers there may be.

This article provides insight in how to use the pub/sub pattern, in Rails, to communicate messages between different system components without these components knowing anything about each other’s identity.

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Ivan Dimoski
Tips for Developing an Android App: My Lessons Learned

This article provides an overview on building a great Android application, from defining an idea to releasing an application to the store. Toptal developer Ivan Dimoski gives us a chance to learn from his experience in making Ooshies, an Android Live Wallpaper designed to give you a hug and make you feel loved each time you interact with your Android device.

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Mahmud Ridwan
Separation Anxiety: A Tutorial for Isolating Your System with Linux Namespaces

Linux namespaces make it possible to run a whole range of applications on a single real machine and ensure no two of them can interfere with each other, without having to resort to using virtual machines. In a single-user computer, a single system environment may be fine. But on a server, where you may want to run multiple services, it is essential to security and stability that the services are as isolated from each other as possible.

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Xiaolei Liu
Bypassing Chinese Internet Censorship: How I Built a Censored Microblog Aggregator

As is known worldwide, the Chinese government enforces strict censorship on the internet. Virtually everything is under the government’s surveillance. In order to be allowed to operate, ISPs and internet content providers in China usually have their own content filtering mechanism for blocking or removing the published content by its users, or even deleting users’ account directly if they are assumed to be illegal under the government policy.

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Ivan Dimoski
Top 10 Most Common Mistakes That Android Developers Make: A Programming Tutorial

There are thousands of different Android powered devices, with different screen sizes, chip architectures, hardware configurations, and software versions. Unfortunately, segmentation is the price to pay for openness, and there are thousands ways your app can fail on different devices.

Regardless of such huge segmentation, the majority of bugs are actually introduced because of logic errors. These bugs are easily prevented, as long as we get the basics right!

Here’s a quick rundown of the 10 most common mistakes Android developers make.

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Balint Erdi
JavaScript Promises: A Tutorial with Examples

Promises are a hot topic in JavaScript, and you should definitely get acquainted with them. They are not easy to wrap your head around, it can take a few articles, and a decent amount of practice to comprehend them. Aim of this article is to help you understand Promises, and nudge you to get more practice using them.

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Marco Mustapic
An iOS Developer’s Guide: From Objective-C to Learning Swift

After 6 years of improving and working on Objective-C, Apple decided to throw another challenge at developers. Once again, iOS developers will need to learn a new programming language: Swift.

Swift 1.0 is already a stable and strong development platform, which is sure to evolve in interesting ways over the coming years. It is a perfect moment to start exploring this new language, as it is the future of iOS development.

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Alex Rattray
Simple Data Flow in React Apps Using Flux and Backbone: A Tutorial with Examples

React.js is a fantastic library. It is only one part of a front-end application stack, however. It doesn’t have much to offer when it comes to managing data and state. Facebook, the makers of React, have offered some guidance there in the form of Flux. I’ll introduce basic Flux control flow, discuss what’s missing for Stores, and how to use Backbone Models and Collections to fill the gap in a “Flux-compliant” way.

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Demir Selmanovic
The 10 Most Common Mistakes Web Developers Make: A Tutorial for Developers

Today we have thousands of digital and printed resources that provide step-by-step instructions about developing all kinds of different web applications. Development environments are “smart” enough to catch and fix many mistakes that early developers battled with regularly. There are even many different development platforms that easily turn simple static HTML pages into highly interactive applications.

All of these development patterns, practices, and platforms share common ground, and they are all prone to similar mistakes caused by the very nature of web applications.

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Matt Hicks
Why Should I Learn Scala?

The popularity and usage of Scala is rapidly on the rise, as evidenced by the ever-increasing number of open positions for Scala developers.

In this article, Toptal engineer Matt Hicks introduces you to the power and capabilities of the Scala language.

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Ryan J. Peterson
Buggy JavaScript Code: The 10 Most Common Mistakes JavaScript Developers Make

At first blush, JavaScript may seem quite simple. Yet the language is significantly more nuanced, powerful, and complex than one would initially be lead to believe. Many of JavaScript’s subtleties lead to a number of common mistakes – 10 of which we discuss here – that are important to be aware of and avoid in one’s quest to become a master JavaScript developer.

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Ilya Sanosyan
Buggy PHP Code: The 10 Most Common Mistakes PHP Developers Make

PHP makes it relatively easy to build a web-based system, which is much of the reason for its popularity. But its ease of use notwithstanding, PHP has evolved into quite a sophisticated language, with many nuances and subtleties that can bite developers, leading to hours of hair-pulling debugging. This article highlights ten of the more common mistakes that PHP developers need to beware of.

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Pooyan Khosravy
Ember Data: A Comprehensive Tutorial for the ember-data Library

Ember Data is a library for robustly managing model data in Ember.js applications. Ember Data provides a more flexible and streamlined development workflow, minimizing code churn in response to what would otherwise be high impact changes. This thorough guide introduces Ember Data’s key constructs and paradigms, demonstrating the value it can provide to you as a developer.

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Ryan Wilcox
The Many Interpreters and Runtimes of the Ruby Programming Language

Which Ruby implementation is right for your project? While the reference implementation (Ruby MRI) remains the interpreter of choice, an alternate Ruby implementation may be right for your project, depending on your operational goals and constraints.

This article showcases the Ruby interpreter implementations and runtimes available today, discussing the advantages and disadvantages of each.

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Jordan Ambra
5 Golden Rules for Great Web API Design

Web services and their APIs abound. Unfortunately, the vast majority are difficult to use. Reasons range from poor design, to lack of documentation, to volatility, to unresolved bugs, or in some cases, all of the above.

Follow the guidance in this post to help ensure that your web API is clean, well-documented, and easy-to-use. Such APIs are truly rare and are therefore much more likely to be widely adopted and used.

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Gergely Kalman
10 Most Common Web Security Vulnerabilities

For all too many companies, it’s not until after a breach has occurred that security becomes a priority. An effective approach to IT security must, by definition, be proactive and defensive. This post focuses on 10 common and significant web-related IT security pitfalls to be aware of, including recommendations on how they can be avoided.

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Alejandro Hernandez
Polymer.js: The Future of Web Application Development?

A year after Google’s launch of Polymer, Toptal engineer Alejandro Hernandez takes it out for a test drive to see if it’s yet ready for prime time. This post explores the maturity and stability of Polymer.js as a foundation for large-scale application development. The results and conclusions from this analysis are provided, along with an introductory overview of the technology.

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Martin Chikilian
Buggy Python Code: The 10 Most Common Mistakes That Python Developers Make

Python’s simple, easy-to-learn syntax can mislead Python developers – especially those who are newer to the language – into missing some of its subtleties and underestimating the power of the language.

In this article, Toptal’s Martin Chikilian presents a “top 10” list of somewhat subtle, harder-to-catch mistakes that can trip up even the most advanced Python developer.

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Diego Castorina
JavaScript Prototype Chains, Scope Chains, and Performance: What You Need to Know

JavaScript is much more nuanced than most developers initially realize. Even for those with more experience, some of JavaScript’s most salient features continue to be misunderstood and lead to confusion. One such feature, described in this article, is the way that property and variable lookups are performed and the resulting performance ramifications to be aware of.

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Patrick Ryder
Buggy C# Code: The 10 Most Common Mistakes That C# Developers Make

C# is a powerful and flexible language with many mechanisms and paradigms that can greatly improve productivity. Having a limited understanding or appreciation of its capabilities, though, can leave one in the proverbial state of “knowing enough to be dangerous”. This article describes 10 of the most common programming mistakes made, or pitfalls to be avoided, by C# programmers.

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Francisco Sanchez Clariá
Data Encoding: A Guide to UTF-8 for PHP and MySQL

Once you step beyond the comfortable confines of English-only character sets, you quickly find yourself entangled in the wonderfully wacky world of UTF-8.

Indeed, navigating through UTF-8 related issues can be a frustrating and hair-pulling experience. This post provides a concise cookbook for addressing these issues when working with PHP and MySQL in particular, based on practical experience and lessons learned.

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Gergely Kalman
Fixing the “Heartbleed” OpenSSL Bug: A Tutorial for Sys Admins

A potentially critical problem, nicknamed “Heartbleed”, has surfaced in the widely-used OpenSSL cryptographic library. The vulnerability is particularly dangerous in that potentially critical data can be leaked and the attack leaves no trace.

As a user, chances are that sites you frequent regularly are affected and your data may have been compromised. As a developer or sys admin, sites or servers you’re responsible for are likely to have been affected.

Here are the key facts you need to know about this dangerous bug and how to mitigate your vulnerability.

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Antonio Bello
iOS User Interfaces: Storyboards vs. NIBs vs. Custom Code

I often hear iOS developers ask some variant of the same key question: “What’s the best way to develop a UI in iOS: through Storyboards, NIBs, or code?”

Answers to this question, explicitly or implicitly, tend to assume that there’s a mutually exclusive choice to be made, one that is often addressed upfront, before development.

I’m of the opinion that there’s no single choice to be made. Rather, each option has its strengths and weaknesses—and there’s no need to use any one of them in isolation.

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Brendon Hogger
Go Programming Language: An Introductory Tutorial

Go is a relatively new language with a number of attractive features. It’s great for writing concurrent programs, thanks to an excellent set of low-level features for handling concurrency. In many cases, though, a handful of reusable abstractions over those low-level mechanisms makes life much easier. This introductory tutorial walks you through building one such abstraction: a wrapper that can turn any data structure into a transactional service in Go.

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Denis Kyorov
Django, Flask, and Redis Tutorial: Web Application Session Management Between Python Frameworks

I love and use Django in lots of my personal and client projects, mostly for those involving relational databases and more classical web applications. However, by design, Django is very tightly coupled with its ORM, Template Engine System, and Settings object. Plus, it’s not a new project: it carries a lot of baggage from the past to remain backwards compatible.

In a few of my client projects, we’ve chosen to give up on Django and use a micro framework like Flask, typically when the client wants to do some interesting stuff with the framework. At the same time, we often need user registration, login, and more, all of which is easily handled with Django.

The question emerged: is Django an all-or-nothing deal? Should we drop it completely from the project, or is there a way to combine some it with the flexibility of other frameworks?

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Diego Castorina
Concurrency and Fault Tolerance Made Easy: An Akka Tutorial with Examples

Writing concurrent programs is hard. Having to deal with threads, locks, race conditions, and so on is highly error-prone and can lead to code that is difficult to read, test, and maintain. This post provides an introductory guide to the Scala-based Akka framework, showing (with code samples) how Akka facilitates and simplifies the implementation of robust, concurrent, fault-tolerant applications.

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Charles Marsh
Python Class Attributes: An Overly Thorough Guide

In a recent phone screen, I decided to use a class attribute in my implementation of a certain Python API. My interviewer challenged me, questioning whether my code was syntactically valid, when it was executed, etc. In fact, I wasn’t sure of the answers myself. So I did some digging.

Python class attributes. No one really knows when (or how) to use ‘em. In this guide, I walk through common pitfalls and conclude with a list of valid use-cases that could save you time, energy, and lines of code.

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Arkadiy Zabazhanov
Elasticsearch for Ruby on Rails: A Tutorial to the Chewy Gem

Elasticsearch provides a powerful, scalable tool for indexing and querying massive amounts of structured data, built on top of the Apache Lucene library.

Building on the foundation of Elasticsearch and the Elasticsearch-Ruby client, we’ve developed and released our own improvement (and simplification) of the Elasticsearch application search architecture that also provides tighter integration with Rails. We’ve packaged it as a Ruby gem named Chewy.

This post discusses how we accomplished this, including the technical obstacles that emerged during implementation.

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Ryan Wilcox
Your Boss Won't Appreciate TDD: Try This Behavior-Driven Development Example

Testing. It always seems to get left to the last minute, then cut because you’re out of time, budget, or whatever else. Management wonders why developers can’t just “get it right the first time”, and developers (especially on large systems) can be taken off-guard when different stakeholders describe different parts of the system.

With behavior-driven development, you can turn testing into a shared process that focuses on the behaviors of the system, why they matter, and who cares.

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Ivan Dimoski
Automated Android Crash Reports with ACRA and Cloudant

Making a basic Android app is easy. But making it reliable, scalable, and robust, on the other hand, can be quite challenging. With thousands of available devices pumped out from tons of different manufacturers, assuming that a single piece of code will work reliably across phones is naive at best. Segmentation is the greatest tradeoff for having an open platform, and we pay the price in the currency of code maintenance, which continues long after the app passes the production stage.

In this post, we’ll walk through a solution: automated crash reporting with ACRA and a Cloudant back-end, all visualizable with acralyzer.

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Balint Erdi
A Guide to Building Your First Ember.js App

As modern web applications do more and more on the client-side (the fact itself that we now refer to them as “web applications” as opposed to “web sites” is quite telling), there has been rising interest in client-side frameworks. There are a lot of players in this field but for applications with lots of functionality and many moving parts, two of them stand out in particular: Angular.js and Ember.js.

Angular.js has already been introduced on this blog, so we’re going to focus on Ember.js in this post, in which we’ll build a simple Ember application to catalog your music collection. You’ll be introduced to the framework’s main building blocks and get a glimpse into its design principles.

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Charles Marsh
Computational Geometry in Python: From Theory to Application

When people think computational geometry, in my experience, they typically think one of two things:

  1. Wow, that sounds complicated.
  2. Oh yeah, convex hull.

In this post, I’d like to shed some light on computational geometry, starting with a brief overview of the subject before moving into some practical advice based on my own experiences in computational geometric programming with Python.

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Alexandre Mondaini Calvão
A Year Building a WebRTC Application: Lessons in Startup Engineering

I’ve been an Engineer at Toptal for just about one year now, working on the same project since I joined the network: Ondello, a service that connects doctors and patients over WebRTC.

When I first joined Ondello, I was hired as a Senior Ruby on Rails Developer, tasked to build a service up from scratch. These days, we’re a team of multiple developers working on a fairly large, complex system.

With this post, I’d like to share the story behind Ondello. Specifically, I’d like to talk about: how a simple application became not-so-simple, and how our use of cutting-edge technologies posed problems I’d never considered before.

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Naftuli Kay
An Introduction to Mocking in Python

More often than not, the software we write directly interacts with what we would label as “dirty” services. In layman’s terms: services that are crucial to our application, but whose interactions have intended but undesired side-effects—that is, undesired in the context of an autonomous test run.

For example: perhaps we’re writing a social app and want to test out our new ‘Post to Facebook feature’, but don’t want to actually post to Facebook every time we run our test suite.

The Python unittest library includes a subpackage named unittest.mock—or if you declare it as a dependency, simply mock—which provides extremely powerful and useful means by which to mock and stub out these undesired side-effects.

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Steven S. Morgan
Anti-Patterns in Telecommuting

As a veteran telecommuter through multiple jobs in my career, I have witnessed and experienced the many joys of being a remote worker. As for the horror stories, I have more than a few I could tell. With a bit of artistic inclination and a talent for mathematics, I also have a fascination with patterns: design patterns, architectural patterns, behavioral patterns, social patterns, weather patterns—all sorts of patterns!

When I first encountered anti-patterns, I discovered a trove of wisdom I wish I had known before I had learned the hard way. Anti-patterns are recognizable repeated patterns that contribute significantly to failure. For example, the manager that keeps interrupting the employee in order to see if the employee is getting any work done is engaging in an anti-pattern that serves to prevent the employee from getting any work done!

Based on my own experiences and experiences of friends and co-workers, I am assembling descriptions of anti-patterns related to telecommuting.

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Radan Skoric
Great Developers Know When and How To Refactor Rails Code

If it ain’t broke, don’t fix it.

It’s a well known phrase, but as we know, most of the human technological progress was made by people who decided to fix what isn’t broken. Especially in the software industry one could argue that most of what we do is fixing what isn’t broken.

Fixing functionality, improving the UI, improving speed and memory efficiency, adding features: these are all activities for which it is easy to see if they are worth doing, and then we argue for or against spending our time on them. However, there is an activity, which for the most part falls into a gray area: refactoring, and especially large scale refactoring.

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Gergely Kalman
With a Filter Bypass and Some Hexadecimal, Hacked Credit Card Numbers Are Still, Still Google-able

In 2007, Bennett Haselton revealed a minor hack with major implications: querying ranges of numbers on Google would return pages of sensitive information, including Credit Card numbers, Social Security numbers, and more. While Haselton’s hack was addressed and patched, I was able to tweak his original technique to bypass Google’s filter and return the same old dangerous results.

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Raoni Boaventura
A Step-by-Step Tutorial for Your First AngularJS App

If you haven’t tried AngularJS yet, you’re missing out. The framework consists of a tightly integrated toolset that will help you build well structured, rich client-side applications in a modular fashion—with less code and more flexibility.

One of the reasons I love working with AngularJS is because of its flexibility regarding server communication. Like most JavaScript MVC frameworks, it lets you work with any server-side technology as long as it can serve your app through a RESTful web API. But Angular also provides services on top of XHR that dramatically simplify your code and allow you to abstract API calls into reusable services. As a result, you can move your model and business logic to the front-end and build back-end agnostic web apps. In this post, we’ll do just that, one step at a time.

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Chris Fox
Why Writing Software Design Documents Matters

Congratulations, you’re an independent developer. From beginnings working maybe as a tester you’ve progressed to a team developer, then a senior developer, and now you’ve made another leap, the biggest of them all, to working directly with clients.

But where the other transitions were linear, this last one was exponential. While in the past you got your marching orders from an employer that worked with clients or was itself in the software business, now all those responsibilities that were once distributed between expert-testing, program management, etc., are all yours. And now you’re working with clients who are not in the software business; they’re in another business that needs a piece of software, and they don’t have a clear and precise vision of what they want from you. This is a far greater challenge than it appears.

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Rodrigo Koch
SQL Database Performance Tuning for Developers

Database tuning can be an incredibly difficult task, particularly when working with large-scale data where even the most minor change can have a dramatic (positive or negative) impact on performance.

In mid-sized and large companies, most database tuning will be handled by a Database Administrator (DBA). But believe me, there are plenty of developers out there who have to perform DBA-like tasks. Further, in many of the companies I’ve seen that do have DBAs, they often struggle to work well with developers—the positions simply require different modes of problem solving, which can lead to disagreement among coworkers.

In this article, I’d like to both provide developers with some developer-side database tuning tips and explain how developers and DBAs can work together effectively.

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Jose Ferreirade Souza Filho
Hunting Memory Leaks in Java

Inexperienced programmers often think that Java’s automatic garbage collection frees them from the burden of memory management. This is a common misperception: while the garbage collector does its best, it’s entirely possible for even the best programmer to fall prey to crippling memory leaks.

In this post, I’ll explain how and why memory leaks occur in Java and outline an approach for detecting such leaks with the help of a visual interface.

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Charles Marsh
Why Are There So Many Pythons? A Python Implementation Comparison

Python is amazing.

Surprisingly, that’s a fairly ambiguous statement. What do I mean by ‘Python’? Do I mean Python the abstract interface? Do I mean CPython, the common Python implementation? Or do I mean something else entirely? Maybe I’m obliquely referring to Jython, or IronPython, or PyPy. Or maybe I’ve really gone off the deep end and I’m talking about RPython or RubyPython (which are very, very different things).

While the technologies mentioned above are commonly-named and commonly-referenced, some of them serve completely different purposes (or at least operate in completely different ways). In this post, I’ll start from scratch and move through the various Python implementations, concluding with a thorough introduction to PyPy, which I believe is the future of the language.

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Anna Chiara Bellini
The Trie: A Neglected Data Structure

From the very first days in our lives as programmers, we’ve all dealt with data structures: Arrays, linked lists, trees, sets, stacks and queues are our everyday companions, and the experienced programmer knows when and why to use them.

In this article we’ll see how an oft-neglected data structure, the trie, really shines in application domains with specific features, like word games.

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Paulo Renato Campos de Siqueira
Scaling Play! to Thousands of Concurrent Requests

Web Developers often fail to consider the consequences of thousands of users accessing our applications at the same time. Perhaps it’s because we love to rapidly prototype; perhaps it’s because testing such scenarios is simply hard.

Regardless, I’m going to argue that ignoring scalability is not as bad as it sounds—if you use the proper set of tools and follow good development practices. In this case: the Play! framework and the Scala language.

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Rogelio Nicolas Mengual
Forex Algorithmic Trading: A Practical Tale for Engineers

A few years ago, driven by my curiosity, I took my first steps into the world of Forex by creating a demo account and playing out simulations (with fake money) using the Meta Trader 4 trading platform.

After a week of ‘trading’, I’d almost doubled my ‘money’. Spurred on by my own success, I dug deeper and eventually signed up for a number of forums. Soon, I was spending hours reading about trading systems (i.e., rule sets that determine whether you should buy or sell), custom indicators, market moods, and more.

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Krešimir Bojčić
What are the Benefits of Ruby on Rails? After Two Decades of Programming, I Use Rails

Sometimes I hear people complaining about their clients, saying that they insist on using Rails, that they’ve had too much Kool Aid. If they are recruiters, they almost feel sick in the stomach from perspective of having to find yet another ROR primadona. From the programmers point of view it sometimes looks like clients don’t have a clue. However, I believe most clients know their options just fine and they still decide to go with Rails.

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Daniel Lewis
Build Dumb, Refactor Smart: How to Massage Problems Out of Ruby on Rails Code

Sometimes, clients give us feature requests that we really don’t like. It’s not that we don’t like our clients, we love our clients. It’s not that we don’t like the feature, most client-requested features are aligned perfectly with their business goals and income. Sometimes, the reason we don’t like a feature request is that the easiest way to solve it is to write bad code, and we don’t have an Elegant Solution on the top of our heads. This will throw many of us on fruitless searches through RubyToolbox, github, developer blogs, and stackoverflow looking for a gem or plugin or example code that will make us feel better about ourselves.

Well, I’m here to tell you, it’s okay to write bad code. Sometimes, bad code is easier to refactor into beautiful code than a poorly thought out solution implemented under a time-crunch.

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Tomislav Capan
Why The Hell Would I Use Node.js? A Case-by-Case Tutorial

Node.js shines in real-time web applications employing push technology over websockets. What is so revolutionary about that? Well, after over 20 years of stateless-web based on the stateless request-response paradigm, we finally have web applications with real-time, two-way connections, where both the client and server can initiate communication, allowing them to exchange data freely. This is in stark contrast to the typical web response paradigm, where the client always initiates communication. Additionally, it’s all based on the open web stack (HTML, CSS and JS) running over the standard port 80.

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Tomislav Kozačinski
How a Single Front-End Engineer Can Replace a Team of Two

Demand within the web design scene today has changed over the past few years: designers with front-end skills, and front-end developers with design skills, are more and more in demand. Yes, you could argue that the jobs are completely different—and maybe you straight-up don’t like one of them—but truth be told, in my six years as a freelance web developer and twelve years as a designer, I’ve learned that it’s much harder to get by as just a web designer or just a front-end developer.

Wearing both hats has a lot of advantages: from a professional perspective alone, you can find work more easily and charge a higher rate because you’re bringing more to the table.

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Alejandro Rigatuso
Growing Growth: Perform Your Own Cohort Analysis with This Open Source Code

But this isn’t just another article about cohort analysis. If you already know the importance of the topic and want to skip the introduction, you can jump to the simulator, where you can either simulate startup growth based on retention, churn, and a number of other factors, or analyze your own PayPal logs with the code I’ve open sourced.

If, however, you don’t realize that these are some of the most important metrics around–continue reading.

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Michael Truog
CloudI: Bringing Erlang's Fault-Tolerance to Polyglot Development

Clouds must be efficient to provide useful fault-tolerance and scalability, but they also must be easy to use.

CloudI (pronounced “cloud-e” /klaʊdi/) is an open source cloud computing platform that is most closely related to the Platform as a Service (PaaS) clouds. CloudI differs in a few key ways, most importantly: software developers are not forced to use specific frameworks, slow hardware virtualization, or a particular operating system. By allowing cloud deployment to occur without virtualization, CloudI leaves development process and runtime performance unimpeded, while quality of service can be controlled with clear accountability.

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Francisco Sanchez Clariá
How I Made a Fully-Functional Arduino Weather Station

I live in Córdoba, Argentina, approximately 130 kilometers (~80 miles) away from the lake where I kitesurf. Thats roughly a two-hour drive, which I can deal with. But I cant deal with the fact that weather forecasts are inaccurate. And where I live, good wind conditions last just a couple of hours. The last thing you want to do is clear up your Monday schedule to go kitesurfing and find yourself cursing the gods on a windless lake after two hours of driving.

I needed to know the wind conditions of my favorite kitesurfing spot—in real time. So I decided to build my own weather station.

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Cameron Barr
Engineering Internals of a RAD Framework... as a PHP Developer with Nooku

Everyone has their own set of tools. As a PHP developer, one of my favorites is a Rapid Application Development framework called “Nooku”. In the words of the development group: “Nooku is more of a web development toolkit than a framework”

In case you are not familiar with it, have a look. It’s an open source project that makes heavy use of industry accepted design patterns to produce highly componentized applications that are easily extensible and reusable (initially created by one of the lead Joomla developers). Out of the box, Nooku gives you a great deal to help get projects off the ground faster. A small, but strong sample:

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Gergely Kalman
How I Made Porn 20x More Efficient with Python Video Streaming

Porn is a big industry. There aren’t many sites on the Internet that can rival the traffic of its biggest players.

And juggling this immense traffic is tough. To make things even harder, much of the content served from porn sites is made up of low latency live streams rather than simple static video content. But for all of the challenges involved, rarely have I read about the developers who take them on. So I decided to write about my own experience on the job.

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