I built RepoExplainer to quickly understand unfamiliar codebases without cloning them locally.

What it does: Paste any public GitHub repo URL and get an AI-generated explanation with architecture diagrams, directory structure, and tech stack breakdown.

How it works: FastAPI backend fetches the repo's directory tree and key files (README, package.json, etc.) in parallel from GitHub's API, then sends that context to Claude for structured analysis.

Try it: https://repex.thienbao.dev.

Tech highlights: - Parallel file fetching with asyncio.gather (70% faster than sequential) - Smart content filtering (100KB limit) to prevent token overflow - Custom tree parser converts GitHub's flat file list into hierarchical structure

Limitations (for now): Public repos only, 20 requests/day per IP, large monorepos may hit token limits.

I'd love feedback on the explanations quality, UX, or anything else

Source Code: https://github.com/BaoNguyen09/repo-explainer