Knip

knip — dead code & unused dependency finder

Knip traces the whole project (not one file at a time) to find what nothing references: unused files, exports, types, and dependencies. This is the mechanical version of "delete code you don't need."

Run

npx knip                  # report unused files, exports, deps, types
npx knip --production     # only production code paths (ignore tests/dev)
npx knip --dependencies   # just unused/unlisted dependencies
npx knip --fix            # auto-remove unused exports/files (review the diff!)

Zero-config for most setups — knip reads package.json + tsconfig.json and has built-in plugins for Vite, Vitest, Next, ESLint, etc. Add a knip.json only if entry points are non-standard.

How to use the output

1. Run npx knip. Group findings: unused files / exports / deps / types.
2. Verify before deleting — knip can flag things reached only by dynamic import, config strings, or framework conventions. Confirm each is truly dead.
3. Remove in small commits (files, then exports, then deps). Re-run knip after.
4. --fix is safe for clearly-unused exports/files, but read the diff — never blind-apply on auth, migration, or public-API code.

Gotchas

• Monorepo: run per-workspace or configure workspaces in knip.json.
• Entry points it can't infer (CLI bins, serverless handlers) → list them in knip.json so it doesn't report them as unused.
• Pairs well as a pre-commit gate (warn, don't block) and before any refactor.