Varun Agrawal, Developer in Berlin, Germany
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Varun Agrawal

Verified Expert  in Engineering

Software Developer

Location
Berlin, Germany
Toptal Member Since
July 28, 2019

With over six years of experience, Varun is a diligent and seasoned senior software engineer who excels at project leadership and managing multinational teams, consistently delivering the best client results. He is language-agnostic and proficient in various programming languages, which enables him to develop diverse projects such as web applications and cross-platform desktop apps. Varun's expertise in DevOps has reduced time-to-market and ensured seamless product launches for clients.

Portfolio

Heylog
JavaScript, Node.js, NestJS, TypeScript, React, Prisma, Cypress, Jest, Cucumber...
Dot Traffic
PHP, JavaScript, CSS, Cloudflare, DevOps, InVision Community, Git, Full-stack...
DS 317 CORP
PHP, HTML, CSS, JavaScript, Stripe, Stripe API, Payment APIs, Git, APIs...

Experience

Availability

Part-time

Preferred Environment

Linux, Windows

The most amazing...

...thing that I've developed is a GUI for the complete administration of the WAMP stack. It is currently used by thousands of developers every day.

Work Experience

Freelance Senior Software Engineer

2022 - 2023
Heylog
  • Developed reusable front-end components in React and MUI.
  • Implemented new back-end features using NX, NestJS, Prisma, and TypeScript.
  • Wrote BDD, unit, and E2E tests using Cucumber, Jest, and Cypress.
Technologies: JavaScript, Node.js, NestJS, TypeScript, React, Prisma, Cypress, Jest, Cucumber, API Connectors, Material UI, User Interface (UI), Responsive Design, Behavior-driven Development (BDD), Code Review, Web Services, RESTful Web Services, Project Management & Work Tracking Tools, UI Components, Testing, SaaS, Cloud Architecture, Logging, Redux, Figma, Algorithms, WebSockets, Pusher, Software Engineering, REST, Test-driven Development (TDD), GitLab CI/CD, Software Development Lifecycle (SDLC), SEO Tools, A/B Testing, PostgreSQL, MERN Stack, Sockets, JavaScript MVC, GraphQL, TypeORM, Responsive UI, GitHub, ESLint, MVC Frameworks, Webpack, Axios, Shell Scripting, Unix Shell Scripting, Monorepos, Nx, API Development, CSS3, Technical Leadership, Database Design, Software Architecture

Freelance Senior Software Engineer

2019 - 2022
Dot Traffic
  • Joined as the sole developer on a legacy project and managed full-stack and DevOps aspects.
  • Led the project on the complete website revamp to a new design for one year and a half.
  • Participated in the hiring process by interviewing, training, and managing junior developers.
  • Improved the page load performance from around five seconds to less than a second with A-star across all categories in GT-Metrix using multi-level caching and code optimizations.
  • Developed plugins to enhance the functionalities of the Invision Community-based website.
Technologies: PHP, JavaScript, CSS, Cloudflare, DevOps, InVision Community, Git, Full-stack, Full-stack Development, Databases, Hosting, Back-end, Amazon Web Services (AWS), Back-end Development, QA Testing, Minimum Viable Product (MVP), Back-end Architecture, API Integration, Front-end, Troubleshooting, Root Cause Analysis, Web Applications, JSON, jQuery, Ajax, REST APIs, Architecture, Plugins, Integration, Optimization, Infrastructure, Web Forms, Web Application Forms, AWS Lambda, Amazon S3 (AWS S3), Web Security, Unix, Amazon CloudFront CDN, LAMP, HTML5, Relational Databases, Unit Testing, Ubuntu, Bash Script, DNS, Amazon RDS, Amazon EC2, XML, API Connectors, User Interface (UI), Responsive Design, Code Review, Web Services, RESTful Web Services, Project Management & Work Tracking Tools, Testing, Cloud Architecture, Logging, Figma, Algorithms, Software Engineering, REST, Software Development Lifecycle (SDLC), SEO Tools, A/B Testing, AWS DevOps, Responsive UI, MVP Design, GitHub, Leadership, Project Management, Casinos & Gaming, Gambling, Retool, MVC Frameworks, Shell Scripting, Unix Shell Scripting, CSS3, Technical Leadership, Database Design, Software Architecture

Freelance Senior Software Engineer

2020 - 2020
DS 317 CORP
  • Implemented a Stripe and Xsolla payment gateway along with the existing Paypal payment gateway.
  • Created sophisticated algorithms to prevent bots from participating in sweepstakes.
  • Cloned some of the existing WordPress plugins and converted them to standalone ones to be used on the website.
  • Developed plugins for an Invision Community-based forum.
Technologies: PHP, HTML, CSS, JavaScript, Stripe, Stripe API, Payment APIs, Git, APIs, Full-stack Development, Full-stack, Databases, Hosting, Back-end, Back-end Development, Minimum Viable Product (MVP), API Integration, Front-end, Troubleshooting, Root Cause Analysis, Web Applications, Object-oriented Programming (OOP), JSON, jQuery, Ajax, REST APIs, Architecture, InVision Community, Plugins, Integration, Optimization, Infrastructure, Web Forms, Web Application Forms, Web Security, Unix, LAMP, HTML5, Relational Databases, Unit Testing, Ubuntu, Bash Script, Amazon EC2, API Connectors, User Interface (UI), Responsive Design, Code Review, Payment Gateways, Web Services, RESTful Web Services, Project Management & Work Tracking Tools, Testing, Cloud Architecture, Logging, Algorithms, CSV, Software Engineering, REST, Software Development Lifecycle (SDLC), SEO Tools, A/B Testing, Responsive UI, GitHub, MVC Frameworks, Shell Scripting, Unix Shell Scripting, API Development, CSS3, Database Design

Software Engineer

2018 - 2019
3T Software Labs
  • Extended the code generator to transpile MongoDB queries to PHP, C#, Node.js, Python, and Ruby code.
  • Migrated the whole codebase independently from the MongoDB Java driver API 2.x to 3.x.
  • Implemented a re-formatting feature for SQL and MongoDB shell code using an ANTLR parser.
  • Converted independent SWT and JFace artifacts into Maven dependencies.
  • Extended an auto-completion framework to provide smart stage-based suggestions in Aggregation Editor.
  • Provided technical support to enterprise customers.
Technologies: SQL, Amazon Web Services (AWS), MongoDB, ANTLR, DevOps, Apache Maven, Java, Code Generators, Microservices, Git, Databases, Hosting, Back-end, QA Testing, JUnit, Agile, Jira, Troubleshooting, Root Cause Analysis, Spring Boot, Spring, JSON, Integration, Optimization, Infrastructure, Amazon DynamoDB, Unix, Unit Testing, Bash Script, VM, Amazon API Gateway, Load Balancers, Amazon EC2, Bitbucket, XML, API Connectors, User Interface (UI), Responsive Design, Multithreading, Code Review, Web Services, Project Management & Work Tracking Tools, Testing, Desktop App Development, Desktop App Design, Cloud Architecture, App Support, Software Troubleshooting, Zendesk, Logging, Algorithms, CSV, Software Engineering, REST, Software Development Lifecycle (SDLC), SEO Tools, A/B Testing, Python, Eclipse SWT, Java 8, PHP 5, PHP 7, GitHub, Leadership, Hibernate, Shell Scripting, Unix Shell Scripting, CSS3, Technical Leadership, Database Design, Software Architecture

Software Engineer

2017 - 2018
SMAL Code
  • Worked primarily in Laravel, Symfony, and React on MVC projects for clients like Vodafone and Elgato.
  • Created products from ideas to production-ready applications in as little as one to three months.
  • Designed and upgraded an SQL schema for medium-sized databases while ensuring optimal performance.
Technologies: SQL, Laravel, Amazon Web Services (AWS), NoSQL, MySQL, JavaScript, DevOps, Frameworks, PHP, REST, API Architecture, Git, Symfony, Web MVC, APIs, REST APIs, Twig, DigitalOcean, Eloquent, Object-relational Mapping (ORM), PHPUnit, Webhooks, Full-stack, Full-stack Development, Databases, Hosting, Back-end, Back-end Development, QA Testing, Minimum Viable Product (MVP), React, TypeScript, Back-end Architecture, API Integration, Next.js, NestJS, Front-end, Troubleshooting, Root Cause Analysis, Automation, Web Applications, Object-oriented Programming (OOP), JSON, jQuery, Ajax, Plugins, Integration, Optimization, Calculators, Web Forms, Web Application Forms, CI/CD Pipelines, Web Security, Vue, Node.js, Unix, OAuth 2, Amazon CloudFront CDN, LAMP, HTML5, Relational Databases, Unit Testing, Ubuntu, Bash Script, DNS, Amazon EC2, XML, Android, API Connectors, User Interface (UI), Responsive Design, Magento, Magento 2, Zapier, Code Review, Payment Gateways, Web Services, Project Management & Work Tracking Tools, Cross-platform App Development, Mobile App Development, SaaS, Cloud Architecture, Algorithms, CSV, Software Engineering, Software Development Lifecycle (SDLC), SEO Tools, A/B Testing, MERN Stack, JavaScript MVC, AWS DevOps, Responsive UI, Microsoft Power Apps, Microsoft Power BI, PHP 5, PHP 7, Drupal, GitHub, Zend Framework, MVC Frameworks, Python, Microservices Architecture, Axios, SQLite, Ruby on Rails (RoR), Angular, AngularJS, Shell Scripting, Unix Shell Scripting, API Development, CSS3, TYPO3, Technical Leadership, Database Design, Software Architecture

Software Engineer

2016 - 2017
parcelLab
  • Created a module in Node.js to predict parcel delivery time based on historical data.
  • Dockerized the service workers on AWS to achieve high scalability while reducing costs.
  • Converted some of the high-load worker threads into an AWS Lambda script to achieve high scalability.
Technologies: SQL, Amazon Web Services (AWS), NoSQL, MongoDB, Redis, DevOps, Node.js, Handlebars, eCommerce, API Architecture, Event-driven Architecture, Git, Docker, Express.js, Scraping, Shell, Bootstrap, APIs, AWS Lambda, Serverless, Object-relational Mapping (ORM), Webhooks, Full-stack, Full-stack Development, Databases, Hosting, Back-end, Back-end Development, QA Testing, React, TypeScript, Back-end Architecture, API Integration, Serverless Architecture, Next.js, NestJS, Agile, Jira, Front-end, Troubleshooting, Root Cause Analysis, Web Applications, Test-driven Development (TDD), JSON, jQuery, Ajax, REST APIs, Architecture, Plugins, Integration, Optimization, Infrastructure, Calculators, Web Forms, Web Application Forms, Amazon Elastic Container Service (Amazon ECS), CI/CD Pipelines, Amazon S3 (AWS S3), Amazon DynamoDB, Unix, LAMP, HTML5, Ubuntu, Bash Script, Data Scraping, DNS, Amazon RDS, Bitbucket, XML, Amazon Simple Email Service (SES), Web Services, Material UI, UI Components, Jest, Cypress, Testing, SaaS, MEAN Stack, Mongoose, Algorithms, CSV, Software Engineering, REST, Microservices, GitLab CI/CD, Software Development Lifecycle (SDLC), SEO Tools, PostgreSQL, MERN Stack, JavaScript MVC, AWS DevOps, GraphQL, IMAP, Email Protocols, TypeORM, Responsive UI, Lambda Functions, NGINX, CakePHP, GitHub, ESLint, MVC Frameworks, Tailwind CSS, Webpack, Microservices Architecture, Vue, Axios, SQLite, Amazon Simple Queue Service (SQS), Shell Scripting, Unix Shell Scripting, API Development, CSS3, Database Design, API Gateways

Software Engineer

2015 - 2015
AdPushup
  • Deployed the CI pipeline on a Jenkins server and integrated it with the GitHub repository.
  • Introduced and implemented integration testing on the company's main product.
  • Created an internal tool to view clients' AdSense reports.
  • Developed back-end features in the Silex framework.
Technologies: Laravel, SQL, PhantomJS, E2E Testing, Jenkins, PHP, CouchDB, Elasticsearch, MySQL, eCommerce, Git, Web MVC, Google Cloud, PostgreSQL, Twig, DigitalOcean, PHPUnit, Full-stack, Full-stack Development, Databases, Hosting, Back-end, Back-end Development, QA Testing, Web Applications, Object-oriented Programming (OOP), JSON, jQuery, Ajax, Plugins, Web Application Forms, CI/CD Pipelines, Unix, OAuth 2, LAMP, HTML5, Integration Testing, Relational Databases, Ubuntu, Bash Script, Zapier, SaaS, Dashboards, Graphs, Data Visualization, Algorithms, CSV, Software Engineering, GitLab CI/CD, Software Development Lifecycle (SDLC), AWS DevOps, Responsive UI, PHP 5, PHP 7, NGINX, GitHub, MVC Frameworks, Microservices Architecture, Shell Scripting, Unix Shell Scripting, CSS3

Google Summer of Code Developer

2014 - 2014
Google
  • Released the first version of SupportFlow independently, a web-based help desk software under the WordPress organization.
  • Implemented a feature to sync support tickets with external mail servers in both directions.
  • Created an advanced parser using regular expressions to hide quoted text in email replies.
Technologies: PHP, WordPress, MySQL, SQL, DevOps, Regular Expressions, eCommerce, Git, Back-end Development, Web Applications, JSON, WordPress Plugins, Unix, Content Management Systems (CMS), Software Engineering, Software Development Lifecycle (SDLC), IMAP, Email Protocols, PHP 5, PHP 7, NGINX, Open Source, GitHub, Shell Scripting, Unix Shell Scripting, CSS3

Varal WAMP

https://www.varalwamp.com/
Varal WAMP is a GUI application written in Visual Studio for the complete administration of the WAMP stack.

I designed a user-friendly interface for one-click switching between different Apache and PHP versions.

Cloud Ping Test

https://cloudpingtest.com/
Cloud Ping Test is an online tool to compare ping times for different regions of various cloud providers, like AWS, Azure, Digital Ocean, and GCP. It receives 6,000+ unique visits each month without SEO.

Survey App

A Windows-based application written in C# and .NET Core that asks interactive, random, but grammatically-correct survey-type questions to users and records their responses in a database. Administrators can also export the answers in different formats like CSV.

Mosh 2

https://github.com/VarunAgw/Mosh-2
Mosh 2 is a wrapper for Mosh written in Bash with a powerful session caching mechanism. It also adds several missing features like SSH multiplexing and increases the SSH connection speed up to six times.

SURLS: A Simple URL Shortener

https://github.com/VarunAgw/SURLS
SURLS is a simple URL shortener written in PHP with support to map lambda functions to aliases. Unlike other URL shorteners, it can live within the users' existing websites, so they don't need to host it on a separate subdomain.

Apaxy 2

https://chrome.google.com/webstore/detail/apaxy-2/pjkfelmkpdpainlidpcaaceahloeljnn
Apaxy 2 is a Chrome extension to replace an Apache and Nginx directory index with a modern interface. It can be used as a Chrome extension on any website or as a server-side module by webmasters.

I implement the keyboard navigation support and also created build scripts using Node.js and Grunt.

TamperHeaders

https://github.com/VarunAgw/TamperHeaders
TamperHeaders is an extension similar TamperMonkey Chrome extension that modifies HTTP requests on the fly. It allows users to easily modify HTTP requests at any stage using just a few lines of code. It also provides programming rules in JavaScript to let users create very advanced rewrite rules.

Hugo Web Developer

https://www.codescan.io/
I added new features to a website based on Hugo and Netlify to improve the website speed using various caching methods and other optimizations to achieve the highest score on different tools like GTmetrix and Google PageSpeed. I also implemented features in the front end using HTML, CSS, JavaScript, and external libraries.

Online Shopping Bot

I developed a bot to make online orders during peak hours on websites like Adidas, Yeezy supply, and Foot Locker. This included:

• Implementing a feature to bypass their captchas using fake user mouse and keyboard actions
• Saving user sessions with high Cloudflare trust scores to be reused later
• Executing a mix of Tor and proxies depending on the needs

Zerodha Kite Enhancements

https://chrome.google.com/webstore/detail/zerodha-kite-enhancements/enpiggkcfokpjboaognglohdbflinhbd
Zerodha Kite Enhancements is a Chrome extension to enhance the functionalities of a large stockbroker. It uses custom-developed server-side APIs to add new features missing in the stockbroker platform.

This extension is highly rated on the Chrome Web Store with only 5-star ratings.

Shopify Lottery

I implemented an API endpoint on Google Scripts where Shopify buyers can sign up for a free lottery. I used Shopify API to validate user email addresses to ensure only genuine shoppers can participate. I then stored the data about the participants on a Google Sheet. At the end of the lottery period, it sends an email to the random winner with a promo code and updates the Google Sheets with the result.

Virtual Number

Created a virtual number on Twilio with the following integrations:

• Forwarding SMS to a real number.
• Forwarding SMS to a Telegram account using Telegram Bot APIs.
• Forwarding incoming phone calls to a real phone number to allow phone calls.

Stock Market

Developed multiple software to work with the stock market.

• Locally hosted, a daily updated screener for US and international stocks, ETF, and Forex pairs.

• Trailing bot. It used broker API to automatically update trailing SL for orders for brokers which doesn't have this trailing SL feature natively.

• Developed another bot to automatically create SL for manual trades and delete SL if the trade was squared-off manually.

• Options screener. Another screener to screen option pairs for stocks and details like PCR and liquidity using market depth.

• Created and managed an extensive database containing 87 million rows with historical data on equities/cryptos/bonds.

• Optimized database using clever optimization and caching levels to finish API requests <50ms.

Google Code Jam

Participated in Google Code Jam and made it through multiple rounds by developing sophisticated algorithms and data structures with efficient space and time complexity. Won a t-shirt from Google for making it through more challenging rounds.

TradingView

• Developed configurable indicators on TradingView to see any script's past 1-year, 5-year, and 10-year performance.
• Developed another feature to calculate crashes from ATH.

This data is presented in a table, and the user configures the location.

Tax Calculator

• Created calculators to calculate income tax and other taxation over different years.
• Built a feature to support a progressive taxation system.
• Implemented in Google Sheets and Excel.
• Implemented advanced features using utilities like XLOOKUP.

Automation

• Developed AutoHotkey script and libraries to automate workflow in Windows.
• Created a workflow in Microsoft Power Automate for desktop and web automation.
• Developed advanced MS Excel formulas and macros to automate workflows.
• Integrated various websites using a Zapier service.
• Created Google Scripts to add new features to Google Sheets.

FFmpeg

• Created an API to generate a GIF preview of a video when hovering.
• Created an API to show a live JPG preview when you scroll over the seek bar.
• Integrated those APIs with the Video.js.
• Optimized the FFmpeg command line to process video faster at the cost of slightly inaccurate results.
• Migrated from Libav to FFmpeg when the former project was abandoned.
• Created a smart cache to avoid processing the same video again for subsequent similar requests.

Languages

Hugo, CSS, Visual Basic, HTML, Java, PHP, SQL, Bash, JavaScript, Curl Language, Google Apps Script, TypeScript, HTML5, Bash Script, XML, Java 8, Visual Basic 6 (VB6), Visual Basic for Applications (VBA), PHP 5, PHP 7, CSS3, Pine Script, GraphQL, C#, C#.NET, Excel VBA, Python

Frameworks

Laravel, Symfony, Express.js, Twig, Eloquent, PHPUnit, Next.js, OAuth 2, Cypress, Jest, Material UI, Electron, JavaScript MVC, CakePHP, Bootstrap, Windows Presentation Foundation (WPF), JUnit, NestJS, Redux, Zend Framework, .NET, .NET Core, Tailwind CSS, Ruby on Rails (RoR), Spring, Angular, Hibernate, AngularJS, Spring Boot, TYPO3

Libraries/APIs

Puppeteer, PhantomJS, Chrome API, REST APIs, Node.js, Telegram Bot API, Handlebars, Stripe, Stripe API, Google Apps, React, jQuery, Pusher, Eclipse SWT, Google Sheets API, API Development, Windows Forms (WinForms), Sockets, Shopify API, Twilio API, FFmpeg, Libav, Vue

Tools

Jenkins, Grunt, Shell, Git, cURL Command Line Tool, Google Sheets, Amazon CloudFront CDN, Bitbucket, Amazon Simple Email Service (SES), Microsoft Excel, Excel 2016, Logging, Mongoose, Figma, GitLab CI/CD, NGINX, GitHub, Webpack, Apache Maven, ANTLR, Jira, Amazon Elastic Container Service (Amazon ECS), Prisma, Cucumber, Zapier, Microsoft Power Apps, Microsoft Power BI, Amazon Simple Queue Service (SQS), AutoHotkey, Retool

Paradigms

REST, E2E Testing, DevOps, On-page SEO, Hosting, Back-end Architecture, API Architecture, Event-driven Architecture, Microservices, Object-relational Mapping (ORM), Automation, Object-oriented Programming (OOP), Automated Testing, Unit Testing, Behavior-driven Development (BDD), Testing, Desktop App Development, MEAN Stack, Microservices Architecture, Database Design, Search Engine Optimization (SEO), Serverless Architecture, Agile, Test-driven Development (TDD)

Platforms

Windows, WordPress, InVision Community, Apache2, Linux, Amazon Web Services (AWS), Magento 2, Magento, DigitalOcean, AWS Lambda, Twilio, Unix, LAMP, Ubuntu, Amazon EC2, Zendesk, Netlify, Contentful, Drupal, Docker, Google Cloud Platform (GCP), Android, Azure, Shopify, Microsoft Power Automate

Storage

MongoDB, MySQL, PostgreSQL, NoSQL, Redis, Databases, JSON, Web Forms, Amazon S3 (AWS S3), Relational Databases, SQLite, Elasticsearch, Google Cloud, CouchDB, Amazon DynamoDB, Cache

Industry Expertise

Project Management

Other

Bots, Scraping, Web MVC, Frameworks, Web Development, APIs, Chrome Extensions, SSH, Regular Expressions, Cloudflare, Full-stack, Full-stack Development, Back-end, Web Scraping, Code Generators, htaccess, eCommerce, Payment APIs, Serverless, Webhooks, Back-end Development, Minimum Viable Product (MVP), API Integration, Front-end, Troubleshooting, Root Cause Analysis, Stock Trading, Stock Market, Web Applications, Ajax, Algorithms, Architecture, Plugins, Integration, Optimization, Infrastructure, Calculators, WordPress Plugins, Web Application Forms, Excel 365, CI/CD Pipelines, Web Security, Chromium, Integration Testing, VM, Data Scraping, DNS, Amazon API Gateway, Load Balancers, Amazon RDS, Data Organization, Data Cleaning, API Connectors, Multithreading, Code Review, Payment Gateways, Web Services, Excel Macros, RESTful Web Services, Project Management & Work Tracking Tools, UI Components, Desktop App Design, Cross-platform App Development, Mobile App Development, Trading, SaaS, Cloud Architecture, App Support, Software Troubleshooting, Tax Systems, WebSockets, Content Management Systems (CMS), Financial Services, CSV, Software Engineering, Software Development Lifecycle (SDLC), SEO Tools, A/B Testing, Fintech, MERN Stack, AWS DevOps, IMAP, Email Protocols, TypeORM, Responsive UI, MVP Design, QR Codes, Lambda Functions, Open Source, Gambling, MVC Frameworks, Axios, Finance, Investment Manager, Investments, Algorithmic Trading, Shell Scripting, Unix Shell Scripting, Technical Leadership, Software Architecture, API Gateways, QA Testing, User Interface (UI), Responsive Design, Dashboards, Graphs, Data Visualization, Leadership, ESLint, Casinos & Gaming, Monorepos, Nx, Telegram Bots, Data Structures, Caching, TradingView, Office 365

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