Artur is available for hire
Hire ArturArtur Grzesiak
Verified Expert in Engineering
Web Extensions Developer
Warsaw, Poland
Toptal member since January 3, 2016
Bio
Artur is a functional programming and TypeScript specialist fascinated by programming, computer science, and mathematics. He is a fast learner and an irrepressibly curious soul, always looking for challenging problems to solve. Artur has a wealthy and unique expertise in broadly understood web technologies.
Portfolio
FleetRover Inc
JavaScript, Chrome Extensions, TypeScript, AG Grid, Wxt, Google Maps API
Self Employed
TypeScript, AG Grid, Web Extensions, Chrome Extensions, Scraping, Web Scraping...
Private Person
Browser Automation, Chrome Extensions, APIs, JavaScript, Selenium, Vercel...
Experience
- Node.js - 13 years
- WebRTC - 12 years
- Web Extensions - 12 years
- Firebase - 11 years
- React - 11 years
- RxJS - 11 years
- React Native - 10 years
- TypeScript - 9 years
Preferred Environment
TypeScript, WebRTC, Web Extensions, React, Firebase, Amazon Web Services (AWS), React Native, HTML DOM, Node.js, Functional Programming
The most amazing...
...thing I created so far is a full-fledged virtual classroom for teaching and learning foreign languages; successfully deployed across multiple US schools.
Work Experience
Browser Extension Expert
2025 - 2026
FleetRover Inc
- Designed and developed a custom extension that integrates with load boards of external providers. Link to webstore: https://chromewebstore.google.com/detail/class8-caller-assistant-l/glbclalbboagmhcibpanomgiegmlknac.
- Overcame complex technical challenges related to automating long-running user flows running in background tabs.
- Found an extremely efficient integration option for one provider that hooked into AG Grid APIs instead of injecting content via the DOM or HTML.
- Created an integration with the client's web apps that allows sending commands to the extension.
- Hooked into the client's web app authentication and authorization to make the user experience as smooth as possible.
- Added rrweb for debugging tasks running in the background.
- Created a robust network interceptor for fetch and XHR APIs.
- Added caching mechanisms to minimize APIs usage (Google Maps and the client's internal).
Technologies: JavaScript, Chrome Extensions, TypeScript, AG Grid, Wxt, Google Maps API
Automation Engineer
2025 - 2025
Self Employed
- Created an automation tool for extracting offering details from Allegro.pl, the largest eCommerce site, overcoming its REST API limitations.
- Automated the opening of Allegro offering lists for provided product EANs, skipped promotional offerings, identified the best offers, and extracted all details, including price and items sold.
- Presented the scraping progress in a table and enabled comparison of the most profitable items, considering warehouse purchase costs, delivery costs, and Allegro.pl's margin.
- Developed a highly effective method for calculating delivery costs and Allegro.pl's margin, improving on the web application's existing method.
Technologies: TypeScript, AG Grid, Web Extensions, Chrome Extensions, Scraping, Web Scraping, Data Scraping
Chrome Extension Developer
2024 - 2025
Private Person
- Developed a browser extension to automate the extraction of reviews from Google Maps.
- Created automation for extracting reviews from Google Maps using a headless browser.
- Discovered a method to extract Google business place IDs directly from the Google Maps HTML source.
Technologies: Browser Automation, Chrome Extensions, APIs, JavaScript, Selenium, Vercel, Next.js, Supabase, Firebase, Scraping, Web Scraping, Data Scraping, Google Maps
Senior Front-end TypeScript/Preact Developer
2024 - 2024
Fit Analytics Innovation GmbH
- Contributed to the creation of a minimum viable product for a new offering.
- Implemented a number of self-contained, responsive components (e.g., dropdown, combo box, grid, tooltip, custom dialog with a focus trap, and drawer) as part of the design system.
- Delivered full support for web accessibility and ARIA standards.
Technologies: Front-end, JavaScript, TypeScript, Functional Programming, Tailwind CSS, Preact, Vite, RxJS, eCommerce, Online Shopping, Figma, Storybook, Playwright, Gherkin, Jest, Signals, Turborepo, Accessibility, Web Accessibility
Full-stack Web Developer | Solution Architect
2023 - 2024
STL Hockey Training LLC
- Designed (code- and UI-wise) and developed a video editor that offers basic drawing, adding audio/mic input, and changing the playback rate of the video (including complete freeze). All modifications are presented on a zoomable timeline.
- Implemented components and UIs based on Figma designs.
- Architected and implemented a web-based player application and a web-based coach application.
- Implemented payment flows based on Stripe Connect.
Technologies: Web Development, Full-stack, Video Editing, JavaScript, FFmpeg, WebAssembly (Wasm), WebRTC, TypeScript, Firebase, Node.js, Stripe, Tailwind CSS, Figma, CSS, Back-end, Back-end Development, Stripe API, Stripe Connect, APIs
Front-end Tech Lead
2022 - 2023
Epistemic AI
- Delivering new features related to search and retrieval of biomedical research and clinical trials.
- Upgraded the codebase to the newest version of TypeScript and 3rd-party dependencies. Replaced react-scripts build with vite. Addressed the most critical issues related to building and dockerized the front-end development environment.
- Replaced AWS Amplify auth flows with a tailored solution. As a result, the UI became consistent, the app logic was more straightforward, and the app bundle was smaller by a few hundred kilobytes.
Technologies: TypeScript, React, Amazon Web Services (AWS), Vite, Material UI, XML, Amazon Cognito, AWS Amplify, Artificial Intelligence (AI), REST, Docker, CSS, APIs
Chrome Plugin Developer
2021 - 2023
Trust & Safety Laboratory Inc.
- Created multiple browser extensions to facilitate internal procedures.
- Worked on scrapping multiple social media sites.
- Developed type-safe patterns for communication between different extension contexts.
- Worked with ChromeDevTools protocol and created an efficient and type-safe abstraction for emulating user interactions with a site.
Technologies: HTML, Chrome Extensions, Web Scraping, Plugins, HTML DOM, TypeScript, Web Extensions, Scraping, HTML5, Webpack, Full-stack, Functional Programming, REST APIs, Vanilla JS, JavaScript, Full-stack Development, Data Scraping, Web Development, CSS, Extensions, Selenium, APIs, Browser Automation
Software Architect | TypeScript Engineer
2019 - 2022
SANS Inc. (Software and Network Solutions Inc.)
- Architected, developed, and designed a virtual language lab consisting of a server and four user-facing applications for teachers, students, admins, and super-admin.
- Used low-level WebRTC with audio and video communication via jitsi‐videobridge.
- Created sophisticated audio recording where users can overwrite, merge with an underlying audio file, and record remote streams.
- Supported dynamic audio routing; divided students into groups; and users can speak with selected students.
- Implemented a custom, browser‐based file manager for class assets like audio, video, text, and HTML.
- Enabled a remote‐control feature of students' recorders and assets with the option to collect their work.
- Implemented dozens of other features like support for exams, displaying external content, screen sharing, raising hands, and quizzes.
- Deployed the product successfully in multiple US-based schools.
Technologies: WebRTC, TypeScript, RxJS, WebSockets, Firebase, Web Audio, Multimedia, Audio Streaming, Full-stack, FFmpeg, HTML5, Firebase Realtime Database, Webpack, ReactiveX, Functional Programming, HTML DOM, REST APIs, Vanilla JS, JavaScript, Full-stack Development, Web Development, Video Editing, CSS, Back-end, Back-end Development, APIs
React Native Developer
2020 - 2021
Outlit Inc
- Created a module for managing WebRTC connections in a React Native dating app.
- Tracked and fixed race condition issues and helped to finish MVP of the product.
- Upgraded parts of the code-base to TypeScript and helped to introduce some better practices.
Technologies: React Native, WebRTC, Firebase, Video Streaming, Google Cloud Platform (GCP), Firebase Realtime Database, Webpack, Full-stack, ReactiveX, WebSockets, Vanilla JS, JavaScript, Video Editing, CSS, Back-end, Back-end Development, APIs, Mobile Development, Mobile App Development, Android
React & WebRTC Developer
2020 - 2020
CR Services AG
- Designed and implemented a reactive architecture for the new front end.
- Implemented a module for managing WebRTC connections.
- Created a very strict error handling policy with a precise error taxonomy.
- Worked on creating matrix tests for WebRTC connections for different environments.
Technologies: React, WebRTC, RxJS, Selenium Grid, Selenium, Webpack, Full-stack, ReactiveX, Functional Programming, WebSockets, HTML DOM, REST APIs, Vanilla JS, JavaScript, Web Development, Video Editing, CSS, APIs, Browser Automation
Expert Developer
2019 - 2020
PionerLabs
- Helped with the digital transformation of one of Norway's biggest companies, Varner.com.
- Led the development of features related to identity management and loyalty programs.
- Architected and implemented the front end with multi-brand and multi-language support for identity and loyalty features.
Technologies: OAuth 2, Google Cloud Platform (GCP), Elixir, Go, PostgreSQL, Docker, Webpack, React, TypeScript, RxJS, Full-stack, ReactiveX, Functional Programming, REST APIs, Vanilla JS, JavaScript, Jest, Cypress, CI/CD Pipelines, Full-stack Development, Web Development, CSS, Back-end, Back-end Development, APIs
Chrome Extension Developer
2019 - 2019
Gartner - Engineering
- Created an extension to augment google search results.
- Implemented integration with back-end REST API and mocks.
- Worked on gtag-related project for supporting A/B tests.
Technologies: React, Chrome Extensions, REST APIs, TypeScript, Web Extensions, Webpack, Scraping, Functional Programming, HTML DOM, Vanilla JS, JavaScript, Web Development, CSS, Extensions, APIs, Browser Automation
Freelance Software Developer
2015 - 2019
Toptal Clients
- Led the creation of core components to handle off-chain mobile transactions for an Ethereum company.
- Built an iOS application to match tenants and landlords in the UK. Functionality includes tenant and property search, real-time chat with photo sharing, push notifications, and live code push updates.
- Developed a Chrome extension for monitoring and collecting information for analytics on employee activity, with an admin panel for real-time insights and statistics and cloud functions back-end.
- Created a tool extension for extracting information from Facebook campaigns and automating the process of starting Facebook campaigns.
- Created a prototype for taking a persistent snapshot of a web page.
Technologies: iOS, Web3.js, RxJS, Firebase, React Native, React, TypeScript, JavaScript, Amazon Web Services (AWS), Firebase Realtime Database, Firebase Cloud Messaging (FCM), Web Scraping, Functional Programming, HTML DOM, REST APIs, Vanilla JS, Full-stack Development, Data Scraping, Web Development, Video Editing, CSS, Back-end, Back-end Development, Stripe, Stripe API, APIs, Browser Automation, Mobile Development, Mobile App Development, Android
Software and Data Engineer
2016 - 2017
Dmx.io
- Developed back-end features in Node.js, MongoDB, and RxJS.
- Contributed to the development of a React Native app.
- Created data scraping functionality for traversing publicly available car portals.
Technologies: Node.js, RxJS, React Native, HTML5, Webpack, Firebase Cloud Messaging (FCM), Full-stack, ReactiveX, Functional Programming, REST APIs, Vanilla JS, JavaScript, Full-stack Development, Data Scraping, Web Scraping, Web Development, CSS, Back-end, Back-end Development, Extensions, Graph Databases, Data Science, APIs, Browser Automation, Mobile Development, iOS, Mobile App Development, Android
JavaScript Developer
2014 - 2016
Validately.com
- Created the recording and playback technology for user interactions with a website/prototype/app. Started mainly with HTML and JavaScript, storing diffs of the DOM.
- Created a high-accuracy proxy server with a caching mechanism.
- Created a tool for recursively downloading and storing assets defined by a web page.
- Created an HTML5-based player based on DOM diffs with support for real-time broadcasting, support for mobile browsers, and synced audio.
- Led the development of multiple cross-platform apps based on WebRTC.
Technologies: Amazon Web Services (AWS), FFmpeg, HTML5, Linux, Node.js, AngularJS, React, RxJS, Web Extensions, Chrome Extensions, React Native, Firebase Realtime Database, Webpack, Full-stack, ReactiveX, Functional Programming, WebSockets, HTML DOM, REST APIs, Vanilla JS, JavaScript, Full-stack Development, Data Scraping, Web Scraping, Web Development, Video Editing, CSS, Back-end, Back-end Development, Extensions, Selenium, APIs, Browser Automation, Mobile Development, iOS, Mobile App Development, Android
Consultant
2013 - 2014
Farsight Software
- Worked on a system for supporting London's administration.
- Added new features and fixed bugs in the existing codebase.
- Collaborated closely with and learned from a very experienced developer.
Technologies: SQL, Windows Forms (WinForms), .NET, C#, Web Development, Back-end, Back-end Development, APIs
Research Assistant
2013 - 2014
Polish-Japanese Institute of Information Technology
- Worked on ways to deal with problems composed of at least two NP-complete sub-problems.
- Created exact solvers for smaller instances and benchmarks.
- Built a web interface for creating and modifying instances.
- Developed a website presenting the aims of the project.
Technologies: Graphviz, Node.js, AngularJS, Java, Web Development
Experience
Software Architect | Typescript Engineer
http://www.sansinc.comA full-fledged virtual classroom for teaching and learning foreign languages.
• Architected, developed, and designed a virtual language lab consisting of a server and four user-facing applications for teachers, students, admins, and super-admin.
• Used low-level WebRTC with audio and video communication via Jitsi Videobridge.
• Created sophisticated audio recording where users overwrite, merge with an underlying audio file, and record remote streams.
• Supported dynamic audio routing; divided students into groups; and users can speak with selected students.
• Implemented a custom, browser‐based file manager for audio, video, text, and HTML class assets.
• Enabled a remote‐control feature of students' recorders and assets with the option to collect their work.
• Implemented dozens of other features like exam support, displaying external content, screen sharing, raising hands, and quizzes.
• Deployed the product successfully in multiple US-based schools.
• Architected, developed, and designed a virtual language lab consisting of a server and four user-facing applications for teachers, students, admins, and super-admin.
• Used low-level WebRTC with audio and video communication via Jitsi Videobridge.
• Created sophisticated audio recording where users overwrite, merge with an underlying audio file, and record remote streams.
• Supported dynamic audio routing; divided students into groups; and users can speak with selected students.
• Implemented a custom, browser‐based file manager for audio, video, text, and HTML class assets.
• Enabled a remote‐control feature of students' recorders and assets with the option to collect their work.
• Implemented dozens of other features like exam support, displaying external content, screen sharing, raising hands, and quizzes.
• Deployed the product successfully in multiple US-based schools.
On Call Coaches – Portal for Players and Coaches
A portal for players and coaches. A player uploads a video for a coach to receive personalized feedback and a performance review.
The heart of the product is the video editor, which offers basic drawing, adding audio/mic input, and changing the playback rate of the video (including a complete freeze). All modifications are presented on a zoomable timeline.
The heart of the product is the video editor, which offers basic drawing, adding audio/mic input, and changing the playback rate of the video (including a complete freeze). All modifications are presented on a zoomable timeline.
StackOverflow Top 2% Overall
I rank in the top 2% overall on StackOverflow. I have been most active in answering JavaScript-related questions, with my recent years' focus on TypeScript. I specifically enjoy answering non-trivial questions, specifically those with a bounty attached.
Validately – Recorder/Player
https://validately.comA tool for recording and playback, including real-time broadcasting interactions with HTML5 sites and apps done purely in JavaScript.
Previously, you could watch videos of users using web apps, but it was not a proper video. I made changes to the DOM recorded and played it back.
I made a custom proxy with long-term asset caching.
Previously, you could watch videos of users using web apps, but it was not a proper video. I made changes to the DOM recorded and played it back.
I made a custom proxy with long-term asset caching.
Education
2009 - 2013
Bachelor of Science Degree in Applied Computer Science
Warsaw University of Technology - Warsaw, Poland
2008 - 2010
Master's Degree in International Economics
Warsaw School of Economics - Warsaw, Poland
2005 - 2008
Bachelor's Degree in Linguistics
University of Warsaw - Warsaw, Poland
Certifications
SEPTEMBER 2022 - PRESENT
Neo4j Certified Professional
Neo4j
DECEMBER 2020 - PRESENT
Deep Learning Specialization
Coursera
JUNE 2017 - PRESENT
Introduction to Probability ‐ The Science of Uncertainty
MITx
DECEMBER 2016 - PRESENT
Learning From Data
CaltechX
JANUARY 2016 - PRESENT
Introduction to Functional Programming
DelftX
MAY 2015 - PRESENT
M102: MongoDB for DBAs
MongoDB University
JANUARY 2015 - PRESENT
University M101JS: MongoDB for Node.js Developers
MongoDB University
JUNE 2013 - PRESENT
Functional Programming Principles in Scala
École Polytechnique Fédérale de Lausanne
JANUARY 2013 - PRESENT
Cryptography I
Stanford University
Skills
Libraries/APIs
ReactiveX, Firebase Web SDK, Node.js, RxJS, React, WebRTC, REST APIs, Preact, FFmpeg, Web Audio, Stripe, Stripe API, Stripe Connect, Windows Forms (WinForms), Web3.js, Selenium Grid, Web Worker, AWS Amplify, Playwright, AG Grid, Google Maps API, Google Maps
Tools
Webpack, Cloudant, Git, Graphviz, Firebase Cloud Messaging (FCM), Amazon Cognito, MainConcept AAC H.264 SDKs, Figma
Languages
HTML, CSS, HTML5, JavaScript, TypeScript, SQL, Java, C#, Go, Elixir, C, Prolog, C++, XML, Gherkin, Haskell, Scala
Frameworks
Chrome, React Native, AngularJS, Vanilla JS, Selenium, .NET, OAuth 2, Jest, Cypress, Material UI, Tailwind CSS, Next.js
Paradigms
Functional Reactive Programming, Functional Programming, HTML DOM, Mobile Development, REST
Platforms
Firebase, iOS, Docker, Google Cloud Platform (GCP), Amazon Web Services (AWS), Linux, Android, Vercel
Storage
Firebase Realtime Database, CouchDB, MongoDB, Redis, NoSQL, PostgreSQL, Neo4j, Google Cloud, Graph Databases
Other
Chrome Extensions, Web Extensions, Scraping, Web Scraping, Full-stack, Data Structures, WebSockets, Full-stack Development, Data Scraping, Web Development, Back-end, Back-end Development, Extensions, APIs, Browser Automation, Front-end, Turborepo, Algorithms, Video Editing, Mobile App Development, Networks, Multimedia, Audio Streaming, Plugins, Video Streaming, Deep Learning, Artificial Intelligence (AI), Proxy Servers, HTTP, Philosophy, Real-time Data, CI/CD Pipelines, Vite, WebAssembly (Wasm), WebCodecs API, Data Science, eCommerce, Online Shopping, Storybook, Signals, Accessibility, Web Accessibility, Probability Theory, Mathematics, Machine Learning, Cryptography, Wxt, Supabase
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