index.mdx

title	Fallow documentation
sidebarTitle	Introduction
description	Get started with Fallow: codebase intelligence for TypeScript and JavaScript. Free static analysis of code and styles: unused code, duplication, complexity, architecture drift, and design-system consistency. Optional runtime intelligence for hot paths, cold paths, and deletion confidence.
keywords	fallow typescript javascript dead code duplication complexity architecture runtime intelligence runtime coverage MCP VS Code CI
mode	wide

Fallow is codebase intelligence for TypeScript and JavaScript.

Use the static layer to find unused code, duplication, complexity hotspots, architecture drift, design-system styling drift, and feature-flag branches across your module graph. Add the optional runtime layer when you want to know what actually executed in production.

Open source analysis for code structure, cleanup, duplication, and styling. Runtime evidence for what actually ran in production.

Start here

npx fallow

No config needed for the first run.

Dead code, duplication, complexity, and styling, in one pass.

npx fallow dead-code
npx fallow dupes
npx fallow health
npx fallow fix --dry-run

What Fallow helps you do

Remove unused files, exports, and dependencies with confidence. Find repeated logic before it spreads. Use complexity and health analysis to focus cleanup work. See hot paths, cold paths, and runtime-backed deletion evidence.

Pick your workflow

Best place to start. Works locally, in CI, and in agent loops. Real-time diagnostics, Code Lens, and one-click fixes in the editor. Structured tool calling for Claude Code, Cursor, and other agents.

Understand the two layers

Static analysis answers: what is connected to what?

Runtime intelligence answers: what actually ran?

They meet in fallow health.

Read the mental model before you set up runtime collection.

Most-used pages