CF FetchCodes Source:

Chrome Web Store: Install CF FetchCodes

GitHub (Open Source): github.com/sayanpaulcse/CF_FetchCodes

What is CF FetchCodes?

It's a browser extension that adds a small widget to every Codeforces problem page. It lets you:

1. See which of your friends solved the problem — detected automatically from your CF friends list.
2. Read their accepted code — with syntax highlighting, right on the page. No navigation needed.
3. Ask AI to explain any solution — a built-in Gemini chat that breaks down the approach, time/space complexity, and logic.
4. Dark Mode for Codeforces — full page dark mode + code-only dark mode with 6 selectable syntax themes.

Feature Breakdown

1. Accepted Codes of Friends

After a contest ends, go to any problem page and click "Show Codes" in the sidebar. The extension checks your friends list using the contest standings API (fast, no scraping), then shows you everyone who got AC. Click any friend's name to expand and read their code with syntax highlighting.

• Smart caching: reopening the same code is instant
• Direct links to the original submission and friend's profile
• Safety-first... human-like delays and batching to respect CF rate limits

2. AI Code Explainer (Gemini-Powered)

Click the "Explain" button above any friend's code to open an AI chat window. It analyzes:

• The approach and algorithm used
• Time complexity and space complexity
• You can ask follow-up questions in the same chat

You can also select any text on a Codeforces page => right-click => "Explain code with AI" for an instant snippet explanation.

Note: Requires a free Gemini API key from Google AI Studio. Your key is stored locally in your browser and is never sent anywhere except directly to Google's Gemini API. We don't have any servers.

3. Dark Mode

Two modes available from the extension popup:

• Full Page Dark Mode: makes the entire Codeforces problem page dark (nav bar, sidebar, test cases, everything).
• Code-Only Dark Mode: applies dark syntax themes only to code blocks. Choose from 6 themes: Monokai, Dracula, Solarized Dark, Nord, GitHub Dark, One Dark.

Privacy

• No external servers — all processing happens locally in your browser
• No analytics, no tracking, no telemetry
• Your Gemini API key is stored in Chrome's local storage and only communicates directly with Google's API
• The extension is fully open source — you can read every line of code on GitHub

IMPORTANT DISCLAIMER

CF FetchCodes is built strictly for UPSOLVING and PRACTICE.

• DO NOT use this extension during live Codeforces rounds.
• DO NOT use AI or any external tool during rated contests.
• The extension is designed to help you learn after a contest is over — study different approaches, understand optimizations, and improve your skills.
• Using AI during live rounds is strictly prohibited by Codeforces rules and undermines the integrity of the platform.

Please read the official Codeforces stance:

• Mike's Blog on AI Rules: the official announcement banning AI tools during live rounds

• General Codeforces Rules

Use this tool to learn and grow — not to cheat your rating.

How to Get Started

1. Install from the Chrome Web Store
2. Make sure you have friends added on Codeforces (star button on their profile)
3. (Optional) Click the extension icon => paste your Gemini API key for AI features
4. Go to any problem page => find "Accepted Codes of Friends" in the sidebar => click "Show Codes"

Feedback, bug reports, and feature requests are welcome! You can comment here, open an issue on GitHub, or reach me at [email protected].

Happy upsolving!