About DiffMergy

DiffMergy was created with a single, unwavering principle: your code never leaves your device. In a world where every developer tool seems to require cloud storage, sign-ups, and data collection, we built something different.

Every comparison, every security scan, every formatting operation runs entirely in your browser using modern Web APIs. No servers. No databases. No telemetry. No tracking of your source code.

We believe that the best developer tools are the ones that respect your privacy while delivering enterprise-grade functionality.

Code Compare & Merge

Side-by-side and unified diff views with syntax highlighting for 30+ languages. Accept/reject changes individually, navigate between changes with keyboard shortcuts, undo/redo decisions, and export standard .patch files. Supports move/refactor detection, inline comments, and auto-save sessions.

Code Review

Upload files or entire folders for instant static analysis. Get code health scores, detect security vulnerabilities, identify code smells, receive refactoring suggestions, and see unit test coverage estimates. Supports drag-and-drop folder upload.

Security Scanning

Detect XSS vulnerabilities, SQL injection risks, hardcoded secrets, unsafe eval() usage, and dozens of other OWASP-category vulnerabilities across 30+ programming languages.

Developer Utilities

JSON/YAML formatting and conversion, regex testing, Base64/URL/HTML encoding, hash and UUID generation, JWT decoding, password generation, HTML/CSS/JS minification, Lorem Ipsum generation, string case conversion, and timestamp conversion.

100% Private

Zero server communication. All processing happens client-side using the Web Crypto API, Web Workers, and modern browser APIs. Your sensitive source code and credentials never leave your machine.

Zero Friction

No sign-up. No installation. No browser extension. No credit card. Just open the website and start working. DiffMergy works on any modern browser across all operating systems.

Enterprise Ready

Used by development teams at companies of all sizes. SOC 2 conscious architecture with no external dependencies for core functionality. Supports 30+ programming languages with syntax-aware analysis.

Open & Free

DiffMergy is completely free to use with no feature gating. We are committed to keeping the core toolkit free and accessible to all developers worldwide.

DiffMergy is built with vanilla TypeScript and Vite, with zero runtime framework dependencies. This keeps the bundle tiny (under 40KB gzipped) and the page load instant. The diff engine is custom-built for accuracy and performance, and syntax highlighting is powered by a lightweight local highlighter.

The application is deployed on Cloudflare's global edge network for sub-50ms response times worldwide.

Have questions, feedback, or want to report an issue? We would love to hear from you.

Visit our GitHub repository to open an issue or contribute to the project.