knip

Knip finds the dead weight in your JavaScript and TypeScript projects: files nothing imports, dependencies you installed and forgot, exports nothing else uses. Run it and it tells you exactly what you can delete. It is free and open source under the permissive ISC license, installed as a single npm package. There is a VS Code extension and an MCP server too, so your AI assistant can flag dead code as you write.

Running it is one command. The work is in the config. Knip reads simple projects automatically, but monorepos, custom frameworks, and build setups usually need a config file and the right plugins so it stops flagging things that are actually used. It ships plugins for most major tools (Next.js, Jest, Storybook, and dozens more), so tuning is mostly picking the right ones, not writing rules from scratch.

This is the tool for shrinking a codebase before a refactor or a dependency audit. Solo or small team: install it, run it in CI, done. Big monorepo: budget an afternoon to dial in the config, then it earns its keep every release by catching cruft before it ships.

The catch is false positives. On a complex setup, knip flags things that look unused but get loaded dynamically or by a tool it has no plugin for. Read the report, do not pipe it straight into fix mode. Once it is tuned it is accurate, but the first run on a messy repo is a conversation, not a verdict.