knip

What is HardGraph? HardGraph publishes curated, provenance-backed agent skills grounded in reproducible vendor documentation.

knip (pronounced with a hard K, Dutch for "to cut") finds and fixes unused dependencies, exports, and files in JavaScript and TypeScript projects. Less code and fewer dependencies mean faster startup, smaller bundles, easier maintenance, simpler onboarding, and a CI gate that prevents dead code from creeping back in.

What knip looks for

Three categories of clutter, comprehensively:

• Unused files — source files nothing imports or references.
• Unused exports — exported symbols (functions, types, constants) nothing consumes. Namespace imports and re-exports are tracked, not just direct imports.
• Unused dependencies — npm packages listed in dependencies / devDependencies that no source file references.

It does this across greenfield and legacy code, in single packages and in monorepos/workspaces, by building a dependency graph from configured entry files and plugins.

Quick start

npx knip                       # analyze the current project
npx @knip/create-config        # scaffold/initialize knip.json

Or install it: npm install -D knip / pnpm add -D knip / bun add -D knip. Editor integrations: @knip/language-server, the VS Code extension, and @knip/mcp for AI agents.

The mental model: entry files, plugins, and the graph

Knip does not guess. It starts from entry files (the places execution or consumption begins) and traces the import graph outward. Anything reachable is "used"; anything not reachable from any entry is reported. This is why configuration matters:

• Entry files (entry, project) — the roots of the graph. If knip reports something as unused that you know is used, an entry file is usually missing or misconfigured.
• Plugins — knip ships plugins for frameworks (Next.js, Astro, Vite, Remix, Storybook, Tailwind, etc.) so framework-specific entry points and conventions are understood without manual configuration.
• Ignore (ignore, ignoreBinaries, ignoreDependencies) — deliberately allowlisted values that knip should not flag (e.g. globally-injected deps, runtime-only binaries referenced in scripts).

Production mode

knip --production analyzes the graph as it would exist in production — excluding dev-only entry files and devDependencies — so you can catch dependencies that leaked into the wrong section or code reachable only in development. Use it before publishing.

Configuration

Knip reads knip.json / knip.jsonc / knip.ts (or a knip field in package.json). A minimal shape:

{
  "entry": ["src/index.ts"],
  "project": ["src/**/*.ts"],
  "ignore": ["src/generated/**"],
  "ignoreDependencies": ["eslint-plugin-x"]
}

For monorepos and workspaces, configuration lives per-package and at the root; packages/docs/src/content/docs/features/integrated-monorepos.md and monorepos-and-workspaces.md cover the workspace model. Configuration hints in the output suggest the exact key to add when knip cannot resolve something.

Running in CI

Knip exits non-zero when it finds unused code, which makes it a CI gate:

knip                         # exits 1 on findings → fails the CI step

Adopt it gradually (guides/adopt-gradually.md) — start with ignores and tighten over time so the gate is green before it blocks merges. guides/using-knip-in-ci.md covers common CI setups.

Reporters and auto-fix

• Reporters (--reporter) control output format (default, symbols, compact, JSON, custom). Pick the one a human or a downstream tool can read.
• Auto-fix (--fix) removes the unused files, exports, and dependencies it found, where safe. Review the diff before committing; some removals (e.g. re-exported barrel entries) have callers knip cannot statically see.

What surprises people

• False "unused" almost always means a missing entry file or plugin. knip is exact about what is reachable; if a used thing is flagged, the graph did not start from the right root. Fix configuration before ignore-listing.
• Namespace and re-exports are tracked. export * and import * as ns do not silently hide usage; knip follows them, but they also make the graph harder to reason about — see guides/namespace-imports.md.
• --fix can remove things with dynamic callers. Anything referenced only through string-based dynamic imports or runtime conventions knip cannot see is a candidate for removal; protect it with ignore or ignoreExports.
• Production mode changes the answer. A dependency that looks used in development can be dev-only; --production re-evaluates the graph without dev entries.

What to verify rather than recall

Plugin names, the exact configuration keys, reporter names, supported config file formats, and CLI flags change between releases. Confirm them against the mirrored corpus under references/vendor/ or knip --help rather than asserting a remembered flag — a renamed flag or key fails silently or misconfigures the graph.

References

• Knip website
• Knip repository
• Getting started
• Configuration reference
• How Knip works