jscpd - Copy/Paste Detector for Source Code for the AI Era

jscpd is the open-source copy-paste detection tool used by thousands of teams worldwide - including engineering pipelines at Microsoft, Salesforce, Deutsche Bahn, and bundled inside super-linter, Mega-Linter, and Codacy.

📈 2,400,000+ weekly downloads on npm
⭐️ 6,000+ stars on GitHub
🌎 224+ supported programming languages and formats

Maintained since 2013 by a single developer.

In 2026, jscpd took on a new role: detecting duplicate code in AI-generated codebases - and got a new engine to match. v5 is a complete Rust rewrite: a native binary with no Node.js required, delivering dramatically faster detection on real-world repositories.

The AI-era toolkit is now built in:

→ AI Reporter - compact, token-efficient output for feeding into LLMs
→ MCP Server in the binary - cpd --mcp serves the Model Context Protocol over stdio, so Claude, Cursor, and Copilot run duplication checks inside their own workflows
→ Agent Skill - one command teaches your AI coding assistant to detect and refactor duplication
→ Cross-format detection - a script block in a .vue file matches a .ts file; fenced code in Markdown matches the language it declares
→ Codebase summaries - top files and folders by size, complexity, and duplication share, so you know where to refactor first
→ Monorepo-aware detection - isolate team-owned packages from each other while still catching duplication against shared code

No other tool in this category does this.

This collective funds the time it takes to keep jscpd maintained, secure, and ready for the next decade of software development.