CF Performance Mirror is a lightweight Chrome extension that shows contest-wise average & median solve times (per index A, B, C…) and high WA% topics directly on Codeforces profile pages. Compact, non-intrusive, and reads only public CF APIs. Install → open any profile → get contest timing + friction insights.

Why I built this

When preparing for contests I kept asking: Which problem types slow me down? How long do I actually take on an A/B/C? CF Performance Mirror surfaces those answers right on the profile, so you can focus training where it helps most.

Key features (quick)

1. Per-index timing: average & median solve time (minutes) per problem index (A, B, C…).
2. High WA% topics: topics ranked by wrong-attempt percentage (contest / overall).
3. Modes: Total / Rated / Unrated contests — view timings separately.
4. Compact UI: anchored under the profile area (like other CF widgets), non-blocking.
5. Privacy first: client-side script only reads public CF APIs (user.status, contest.list, user.rating). No personal 6. data collected or sent to servers.

UI preview of CF Performance Mirror on a user profile

Shows contest-wise timings

Shows contest-wise and global WA% analysis

How to use

1. Install the extension from the Chrome Web Store https://chromewebstore.google.com/detail/cf-performance-mirror/lpbkkcofbkmghobeeeipbdgohbckcdgj.
2. Open any Codeforces profile: https://mirror.codeforces.com/profile/
3. Scroll to the profile area — the CF Performance Mirror card loads under the existing widgets.
4. Toggle Div categories and Total/Rated/Unrated to compare. Click a WA% topic to note weak areas.

Short privacy note

CF Performance Mirror only accesses public Codeforces API endpoints to read profile/submission/contest metadata. It does not collect, store, or transmit personal data to any server. All analysis runs client-side in your browser.

Feedback & Suggestions

If you have any suggestions, feature requests, or notice any issues, please let me know in the comments.

GitHub: https://github.com/your-username/cf-performance-mirror

Your feedback will help me improve and upgrade this extension for everyone.