Fallow — Fallow scans TypeScript and JavaScript codebases to find health issues, duplication, and unused code, providing insights from one graph.

Analyzed by · Developer Tools · Code Quality · View on GitHub

What It Is

Imagine Fallow as a super-powered X-ray machine for your TypeScript and JavaScript code. Instead of just checking for obvious breaks, it builds a detailed map (a 'graph') of how all your code pieces connect. This map lets it spot hidden problems like functions doing the same thing, code that's never used, or parts of your system that are getting too tangled.

This matters because messy, complex, or duplicated code slows down development, introduces bugs, and makes onboarding new engineers a nightmare. Fallow helps teams catch these issues early, even in pull requests, preventing technical debt from piling up and keeping the codebase healthy and maintainable.

Fallow GitHub repository card

License Verdict

MIT License — Build and Sell Freely — Commercial Use Approved • No Copyleft Restrictions

The MIT License allows you to use, modify, distribute, and sell software created with Fallow, even for commercial purposes. You only need to include the original copyright and license notice in your derivative works. There are no copyleft provisions, so you don't have to open-source your own code.

How to Use It

Fallow can be run directly via npx for a quick check, or installed as a dev dependency for project-specific use. It requires no TypeScript compiler or Node.js runtime for its core analysis, making setup straightforward.

Prerequisites:

Estimated setup time: 5 minutes.

npx fallow
npm install --save-dev fallow
npx fallow audit

What I'd Build With This

Code Health Scorecard for Open Source (micro-saas)

Build a web service that takes a GitHub repo URL (JS/TS), runs Fallow analyses (health, dead-code, dupes), and generates a public 'Code Health Scorecard'. This helps maintainers quickly identify areas for improvement and attracts contributors who value clean code. Charge maintainers a monthly fee for automated scans and detailed reports.

Effort: 1 Week Build Time · Target: Open Source Project Maintainers, Technical Bloggers · Pricing: $19/month for basic, $49/month for advanced features

Monorepo Guardian (saas)

Develop a SaaS platform specifically for monorepos that integrates Fallow to monitor architecture boundaries, circular dependencies, and design system drift across multiple packages. Provide a dashboard to visualize codebase health trends over time, enforce custom rules, and offer automated suggestions for refactoring. Teams pay per active developer seat.

Effort: 3 Months Build Time · Target: Engineering Teams in Monorepos, Large Scale Web Agencies · Pricing: $29/developer/month

Custom Static Analysis for Regulated Industries (enterprise)

Offer a bespoke service to enterprise clients in regulated industries (e.g., FinTech, Healthcare) that need highly customized static analysis beyond standard linters. Leverage Fallow's extensibility and Rust performance to build custom 'guard' rules for compliance, security patterns, and specific architectural constraints. Deliver on-premise or as a private cloud instance, with consulting and support.

Effort: 6 Months Build Time + Consulting · Target: Large Enterprises, Highly Regulated Companies · Pricing: Custom pricing, $50k+/year retainers

Sai Pavan Gopularam's Take

I love tools that get straight to the point and actually save developer time. Fallow's ability to quickly highlight issues like dead code or complexity hotspots, especially in a PR, is a huge win. If I were building a Code Climate competitor for TS/JS, I'd estimate I could capture 0.5% of the market within 3 years, generating $1.5M ARR.

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