Never Miss a Coding Contest Again — AlgoRadar Chrome Extension

Revision en7, by stepwise, 2026-07-14 14:18:17

Hello everyone,

I kept forgetting upcoming contests across Codeforces, AtCoder, LeetCode, and CodeChef, so I built a single extension that keeps everything in one place. AlgoRadar is an open-source extension designed to let you view upcoming competitive programming rounds from multiple platforms seamlessly.

✨ Features at a glance:

  • All Major Platforms: One unified interface for Codeforces, LeetCode, AtCoder, CodeChef, and more soon.
  • Smart Filtering: Filter contests by platform and time range ("Today", "This Week", or "This Month") so you only see events that matter to you.
  • Live Countdown Timers:See exactly how much time remains before registration or contest start, automatically adapted to your computer's local timezone..
  • Fast Performance:/b> Only 88 KiB in size with a clean dark theme that keeps data fresh in the background using periodic synchronization and caching


Technical Implementation & Architecture

For those interested in how it works under the hood:
  • Instant Popup Loading:Since data is pre-synchronized, opening the extension doesn't trigger multiple external API requests, ensuring zero interface lag.
  • Server-side Synchronization:Instead of fetching schedules every time the popup opens, a backend periodically syncs contest data and serves cached results to the extension. This keeps popup load times fast while reducing unnecessary client-side requests.
  • Resilient Data Fetching: Some contest platforms are protected by Cloudflare, making scheduled fetches unreliable from standard environments. To handle this, the backend uses a serverless synchronization layer with cached responses, avoiding frequent failed requests.

The project is 100% open-source. No ads, no tracking, and no user credentials are collected.

Check it out and let me know your thoughts!

Get it on Chrome Web Store Star/Contribute on GitHub

Tags codeforces, tool, chrome extension

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en14 English stepwise 2026-07-14 14:38:28 0 (published)
en13 English stepwise 2026-07-14 14:37:38 16 Tiny change: 'en missed or forgot about upcoming ' -> 'en missed upcoming '
en12 English stepwise 2026-07-14 14:36:16 1 Tiny change: 'ata fresh./li>\n</ul' -> 'ata fresh.</li>\n</ul'
en11 English stepwise 2026-07-14 14:34:46 234
en10 English stepwise 2026-07-14 14:30:15 441
en9 English stepwise 2026-07-14 14:20:40 3
en8 English stepwise 2026-07-14 14:18:55 2 Tiny change: 'tore</a>\n<a href=' -> 'tore</a>\n\n<a href='
en7 English stepwise 2026-07-14 14:18:17 1298
en6 English stepwise 2026-07-14 13:58:20 66
en5 English stepwise 2026-07-14 13:55:17 15
en4 English stepwise 2026-07-14 13:54:17 625
en3 English stepwise 2026-07-14 13:49:50 42
en2 English stepwise 2026-07-14 13:46:29 325
en1 English stepwise 2026-07-14 13:36:58 1298 Initial revision (saved to drafts)