Fallow documentation
Codebase intelligence for TypeScript and JavaScript. Fallow reports health, complexity, duplication, architecture drift, styling drift, and unused code from one graph of your repository.
Fallow is codebase intelligence for TypeScript and JavaScript. One command reads your whole repository as one graph and shows:
- where the code is hard to change (complexity hotspots and a health score)
- where the architecture drifts (boundary rules and circular dependencies)
- what is copied (duplication)
- where the UI drifts from your design system (styling drift)
- what nothing uses (unused files, exports, and dependencies)
- where the feature flags are
To learn which code executed in production, add the optional runtime layer.
Start here
Run fallow without installing
npx fallowThe first run needs no config.
Read the results
One pass reports health, duplication, and unused code. For styling drift, run
fallow auditorfallow health --css.Go deeper
npx fallow dead-code npx fallow dupes npx fallow health npx fallow fix --dry-run
What fallow helps you do
Find unused files, exports, and dependencies, and remove them.
Find repeated logic before it spreads.
Rank code by complexity and health, and fix the worst first.
Confirm exact symbol use, class contracts, affected files, and the tests to run.
See hot paths and cold paths, and back a delete with production data.
Pick your workflow
Start here. The CLI runs locally, in CI, and in agent loops.
Get real-time diagnostics, Code Lens, and one-click fixes in the editor.
Give Claude Code, Cursor, and other agents structured tool calls.
Understand the two layers
Static analysis tells you which code is connected to which. Production data from Fallow Cloud tells you which code actually ran. fallow health shows both.
Learn how the two layers differ before you set up runtime collection.