---
title: "Fallow"
description: "Find dead code, duplication, and complexity hot spots with Fallow, then tune focused ignores for framework conventions."
date: "2026-03-26"
tags: ["Fallow","Dependencies","Code Quality","TypeScript"]
canonical: "/learn/guides/project/fallow"
---

import { Aside, Code } from '@astrojs/starlight/components'
import Source from './fallow.config.json?raw'

## What is Fallow?

Fallow is a codebase analysis tool for TypeScript and JavaScript. A single run
checks for dead code, duplicated logic, and maintainability problems such as
complexity hot spots.

It complements a linter: a linter examines individual files for suspicious
syntax and style, while Fallow follows relationships across the project to find
unused files, exports, types, and dependencies.

## Installation

Install Fallow as a development dependency so everyone on the project uses the
same version:

```bash
pnpm add --save-dev fallow
```

Wire the local binary into `package.json`:

```json title="package.json"
{
  "scripts": {
    "fallow": "fallow"
  }
}
```

Run the complete analysis with:

```bash
pnpm fallow
```

The bare command runs all three analysis groups. During focused work, you can
run `pnpm fallow dead-code`, `pnpm fallow dupes`, or `pnpm fallow health`.

## Configuration

Fallow works without configuration. When a framework or build tool loads a file
by convention, however, static analysis may not see the connection. Create a
`.fallowrc.json` and add only those paths to `ignorePatterns`:

<Code code={Source} lang="json" title=".fallowrc.json" wrap />

The `$schema` entry enables validation and editor completion.

## Practical workflow

1. Run `pnpm fallow`.
2. Review each finding before deleting code or dependencies.
3. Fix genuine findings in small, testable changes.
4. Add a focused ignore only when usage depends on a convention Fallow cannot
   discover.
5. Re-run the analysis until its output is useful and understood.

For automatic cleanup, preview changes first with
`pnpm fallow fix --dry-run`. Commit or stash unrelated work before applying a
fix without `--dry-run`.

## References

- [Fallow installation](https://docs.fallow.tools/installation)
- [Fallow quick start](https://docs.fallow.tools/quickstart)
- [Migrating from Knip](https://docs.fallow.tools/migration/from-knip)
- [Fallow configuration](https://docs.fallow.tools/configuration)