Tim Zadorozhny, Developer in Lviv, Ukraine
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Tim Zadorozhny

Verified Expert  in Engineering

Front-end Developer

Lviv, Ukraine
Toptal Member Since
June 3, 2019

Tim is an experienced and driven front-end developer with expertise implementing challenging HTML5 apps. He has a solid background in computer science, mathematics, and algorithms, making him an excellent choice for complex, detail-oriented jobs with multi-layered requirements. Tim is passionate about, and stays up-to-date on the latest technologies and trends, ensuring high-quality solutions in his work.


JavaScript, HTML5, Python, CSS, HTML, Architecture, Animation
Haskell, Knockout (Knockout.js), JavaScript, HTML5, Data Scraping, Web Scraping...
Google App Engine, Python, Canvas 2D, JavaScript, HTML5




Preferred Environment

MacBook, Git, Visual Studio Code (VS Code), ChatGPT, OpenAI GPT-3 API, OpenAI GPT-4 API

The most amazing...

...project I've worked on was an online PowerPoint clone similar to Google Presentations, including an online editor, player, and social browsing site.

Work Experience

Front-end Software Engineer

2014 - 2018
  • Implemented front-end features which allowed annotation of videos with additional content such as text, links, and shopping ads.
  • Implemented supporting back-end parts in Python and another proprietary technology.
  • Experimented with innovative playback solutions of video in HTML5 clients.
Technologies: JavaScript, HTML5, Python, CSS, HTML, Architecture, Animation

Front-end Software Engineer and Team Lead

2012 - 2014
  • Designed and implemented an HTML5-based messaging solution, and an HTML5-based audio and video call platform with WebRTC.
  • Designed the UI prototyping in close collaboration with the design team.
Technologies: Haskell, Knockout (Knockout.js), JavaScript, HTML5, Data Scraping, Web Scraping, Bootstrap, Design

Software Engineer and Team Lead

2010 - 2012
  • Designed and implemented a PowerPoint-like web-application using HTML5.
  • Designed and implemented the back end, using Python on Google App Engine. I was the tech lead for both the front end, and back end.
  • Learned how to use Canvas, and loved this technology for its simplicity, performance speed, and wide availability.
Technologies: Google App Engine, Python, Canvas 2D, JavaScript, HTML5

Software Engineer and Team Lead

2009 - 2010
Intellias, Ltd.
  • Upgraded the old back-end system to a fresh and popular Java framework.
  • Implemented an HTML5 web-based UI to replace old clients.
Technologies: Java

Software Engineer and Team Lead

2006 - 2009
  • Charged the Module Adapter for the Vodafone GR Mobile Operator and Ericsson.
  • Designed and implemented a load balancing component to process end-user charging traffic.
  • Developed an HTTP Service Gateway for a TIM and WIND Mobile Operator, and Ericsson.
  • Replaced the old custom Service Gateway with an Ericsson-based solution, providing backward compatibility to existing clients.
  • Developed the end-user mobile web portal development for TIM and WIND Mobile Operator, and Ericsson.
Technologies: XML, Java

YouTube Annotations

Implemented front-end features which allowed the annotation of videos with additional content, such as text, links, and shopping ads. Developed a modern alternative to deprecated video annotations with InfoCards.

Implement the necessary back-end parts in Python. I created a unique solution for playing two videos in sync, one inside the other, as well as sign language translations.

Wire Instant Messaging App

Using an HTML5 client, I implemented both a text-based messaging app with file and image attachments, as well as audio and video call capabilities using WebRTC.


This Swedish startup helps bloggers and simple site creators with a unique web tool.

I designed and implemented a PowerPoint-like web application using HTML5, and developed the back end using Python with the Google App Engine.

One of the most challenging tasks was the implementation of the algorithm and UI for removing backgrounds from images. Not only solid white or other colors, but any background. This is done with a little help from the user who provides marking points.

The http://remby-os.appspot.com/ link is kept for historical reasons since the project has now been shut down, with only a few elements still functioning.
2005 - 2006

Bachelor’s Degree Conferred Via Academic Exchange in Computer Science

KTH Royal Institute of Technology - Stockholm, Sweden

2001 - 2006

Bachelor’s Degree in Computer Science

University of Crete - Heraklion, Greece


HTML5 Canvas, Node.js, React, Vue, Three.js, Google Cloud API, D3.js, WebGL


Canvas 2D, ChatGPT, Git, MongoDB Atlas


Express.js, Flutter, Bootstrap, Knockout (Knockout.js), Tailwind CSS, Svelte


HTML, CSS, Python 3, JavaScript, HTML5, CSS3, Processing, Dart, TypeScript, Java, Python, Haskell, XML


Responsive Coding, Functional Programming, Object-oriented Programming (OOP), Concurrent Programming


Google App Engine, Amazon Web Services (AWS), Mobile, Firebase, Docker, Google Cloud Platform (GCP), Visual Studio Code (VS Code)


Google Cloud, PostgreSQL, MongoDB


HTML5 Video, Chrome Extensions, Web Development, Front-end, APIs, Processing.js, Front-end Development, 2D Games, Game Development, Data Scraping, Web Scraping, Architecture, Animation, Full-stack, Vue Router, App Engines for Python, SVG, OpenAI GPT-3 API, OpenAI GPT-4 API, Design, MacBook

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