Toptal Engineering Expert
Toptal Engineering Blog
The Toptal Engineering Blog is a hub for in-depth development tutorials and new technology announcements created by professional software engineers in the Toptal network.
Featured in
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?

Denis Kyorov
Denis is an experienced Python/Go developer (7+ years) who has contributed to a wide range of challenging back-end projects.
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.

Diego Castorina
Diego has been a senior freelance engineer for the likes of Italian telecom powerhouse Italtel. He also cofounded a web-based CRM business.
World-class articles, delivered weekly.
By entering your email, you are agreeing to our privacy policy.
Mobile App Development vs. Mobile Web Development: When, Why, and How
Mobile web development—optimizing web apps for mobile devices—is necessary for modern apps. Discover the best methods and tools for the development of highly functional, intuitive, and easy-to-use mobile web apps.

Tomas Agrimbau
Tomas is a seasoned web developer proficient in both front-end and back-end development with PHP. He excels in responsive web design.
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: when (or how) to use them. In this guide, I walk you through common pitfalls and conclude with a list of valid use cases that could save you time, energy, and lines of code.

Charles Marsh
Charles has been an engineering lead at Khan Academy, Cedar, and Spring Discovery.
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.

Arkadiy Zabazhanov
Arkadiy is a senior Ruby on Rails developer. He enjoys working with databases and open-source initiatives on GitHub.
Modernizing Legacy Software: MUD Programming Using Erlang and CloudI
The need to adapt legacy code and systems to meet modern day performance and processing demands is widespread. This post provides a case study of the use of Erlang and CloudI to adapt legacy code, consisting of a decades-old collection of multi-user game software written in C, to the 21st century.

Michael Truog
Michael is a distributed systems and fault tolerance expert, having worked with AT&T, E*Trade, Nokia and others.
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.

Ivan Dimoski
Ivan is an accomplished Android developer and consultant with six years of experience developing user-friendly applications.
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.

Balint Erdi
Balint has been practicing TDD since before it became popular. He was a classic PHP coder, and has since moved on to Java, Python, and Ruby.
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.

Charles Marsh
Charlie (BCS, Princeton) has been an engineering lead at Khan Academy, then Cedar, and nowadays does ML at Spring Discovery.
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.

Alexandre Mondaini Calvão
Alexandre is an expert Ruby on Rails developer who is also experienced with Java and various front-end technologies.
An Introduction to Python Mocking
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 Python application, but whose interactions have intended but undesired side-effects—that is, undesired in the context of an autonomous test run.

Naftuli Kay
From building custom TCP servers to large-scale finance apps, Naftuli’s breadth of experience makes him a top-of-class dev and sysadmin.
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.

Steven S. Morgan
Steven is an expert Java architect and developer with extensive experience in distributed architectures, scalable solutions, and more.
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.

Radan Skoric
Radan is a senior full stack developer who splits his time between writing advanced, but simple, Ruby code and leading a team of developers.
Credit Card Hacks: With Some Tricks, Hacked Card Numbers Are Still, Still Googleable
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.
Toptal Talent Network Experts
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 AngularJS tutorial, we’ll do just that, one step at a time.

Raoni Boaventura
Raoni’s BCS and decade of web-dev experience have seen him lead and contribute to a wealth of projects using RoR, JS, and PHP, among others.
Responsive Web Design Media Query Examples Explained
RWD allows a site to adapt for optimal viewing on a variety of devices that range in size based on a media query for mobile and other screen widths. Nowadays, your website will be visited by a wide variety of devices: desktops with large monitors, mid-sized laptops, tablets, smartphones, and more. To achieve an optimal user experience, your site should be adjusting its layout in response to these varied devices (i.e., to their varied screen resolutions and dimensions).

Tomislav Krnic
Tomislav is a freelance web developer and designer with over 10 years of experience working independently and as a project leader.
Most-read Articles

An Angular 5 Tutorial: Step by Step Guide to Your First Angular 5 App
World-class articles, delivered weekly.
Toptal Developers
- Android Developers
- App Developers
- AWS Developers
- Azure Developers
- BigCommerce Developers
- Blockchain Developers
- Coders
- Database Developers
- Embedded Software Engineers
- Flutter Developers
- HTML5 Developers
- Java Developers
- Joomla Developers
- Kubernetes Developers
- Laravel Developers
- Magento Developers
- .NET Developers
- Next.js Developers
- Odoo Developers
- Outsourced Developers
- PHP Developers
- Power BI Developers
- Prototype Developers
- Python Developers
- React Developers
- React Native Developers
- Remote Developers
- Ruby on Rails Developers
- Salesforce Developers
- Security Engineers
- SharePoint Developers
- Shopify Developers
- Software Developers
- Squarespace Developers
- Startup Developers
- Svelte Developers
- Twilio Developers
- Vue.js Developers
- Web Developers
- Web Scraping Developers
- WooCommerce Developers
- WordPress Developers
- View More Freelance Developers
Join the Toptal® community.





















