Hey Codeforces!
CF Stopwatch — a tiny browser extension I built that auto-injects a stopwatch directly into Codeforces problem pages. No setup, no manual effort — it just works.
TL;DR
If you want to track how long you actually spend on a problem without leaving the page or starting/stopping a separate timer, CF Stopwatch does that for you automatically.
Why I built it
I kept losing track of how long I was spending on problems. Opening a separate timer, remembering to start/stop it, or finding out it had been running in another tab broke my focus. I wanted a timer that lives inside Codeforces itself and requires zero interaction.
What it does
- Anti-panic buffer — A 60-second delay before the timer starts so you can read the problem and decide whether to attempt it (or manually start earlier). No clock-stress the moment the page opens.
- Auto-stop on Accepted — The extension polls the Codeforces API every 5 seconds and freezes the timer as soon as your submission receives Accepted. (You must be logged in for this to work.)
- Multi-attempt support — Hit Reattempt to reset the clock for a fresh try. Previous AC verdicts are ignored for the new attempt.
- Smart persistence — The timer only runs while the tab is open. Close the tab and it freezes; reopen and it resumes exactly where it left off. Nothing runs silently in the background.
- Adaptive theme — The widget reads colours from the Codeforces page at runtime so it blends with light/dark/custom themes automatically.
Screenshots
Installation
Chrome / Chromium
- Download and unzip
cf-stopwatch-chrome - Go to
chrome://extensions, enable Developer mode - Click Load unpacked → select the folder
Firefox
- Download and unzip
cf-stopwatch-firefox - Go to
about:debugging → This Firefox → Load Temporary Add-on - Select
manifest.json
Download From Here
GitHub: pratikrkcha/CF-Stopwatch
If you find it useful, a star on the repo would mean a lot. Feedback and suggestions welcome — drop them in the comments below!
— Pratik Rakhecha
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