jscpd

Copy/paste detector for programming source code. jscpd finds duplicated blocks across 224 language formats, including cross-format detection for Vue, Svelte, Astro and Markdown, and writes the result with 15 reporters: console, JSON, XML, CSV, HTML, Markdown, SARIF, Code Climate, OpenMetrics, badge, Xcode, a token-efficient AI format and more.

This package ships the same self-contained Rust binary as the npm and crates.io releases, as platform wheels for macOS (arm64, x64), Linux (glibc and musl, x64 and arm64) and Windows (x64, arm64). It installs the jscpd and cpd commands. No Python code, no Node.js runtime.

Install

pip install jscpd          # or: pipx install jscpd / uv tool install jscpd
jscpd /path/to/code

uvx jscpd /path/to/code    # run without installing

What it finds

• Exact clones by default; --min-tokens and --min-lines set the size.
• Type-2 clones: --ignore-identifiers, --ignore-literals and --ignore-annotations catch blocks that differ only in names, literal values or annotations.
• Type-3 near-miss clones: --max-gap-lines N merges copies with a few inserted or changed lines; --similarity 0.85 compares JavaScript and TypeScript functions by syntax-tree structure.
• Only new duplication: --baseline or --baseline-from-ref origin/main with --fail-on-new-clones tolerate legacy clones and fail CI on regressions.
• Threshold: --threshold 5 fails the run when more than 5% of the code is duplicated.

Also --blame (git authorship per clone), --summary (refactoring hotspots by tokens, lines, size and complexity), --mcp (a built-in MCP server so an AI assistant can query the scan), --skip-local and --skip-isolated for monorepos, and .jscpd.json configuration. Full CLI reference: https://jscpd.dev

pre-commit

No Node.js needed; the hook installs this wheel:

repos:
  - repo: local
    hooks:
      - id: jscpd
        name: jscpd - copy/paste detector
        entry: jscpd
        language: python
        additional_dependencies: ['jscpd==5.3.1']
        args: [--threshold, "5", --reporters, console,silent]
        pass_filenames: false
        always_run: true

The repository also publishes a .pre-commit-hooks.yaml, so repo: https://github.com/kucherenko/jscpd with a v5.2.1 or later rev works without additional_dependencies.

Links

• Documentation: https://jscpd.dev
• Source and issues: https://github.com/kucherenko/jscpd
• Changelog: https://jscpd.dev/getting-started/changelog
• GitHub Action, Docker image, npm, crates.io, Homebrew and Nix installs: https://jscpd.dev/getting-started/installation