Regex Tester
Test regular expressions with live matches, group capture, and replace mode.
Why Use DiffMergy’s Regex Tester?
DiffMergy’s Regex Tester provides a real-time playground for building and testing regular expressions against sample text. With instant match highlighting, capture group display, and comprehensive flag support, you can craft perfect patterns without guesswork.
Whether you are writing validation rules, search patterns, or text extraction logic, the live preview shows exactly what matches and why. All processing is local, so even sensitive test data never leaves your browser.
100% Private — No Server Upload
All processing happens entirely in your browser using Web Workers and modern browser APIs. Your sensitive source code, credentials, and files never leave your device — no servers, no databases, no tracking, no sign-up required.
Fast & Reliable
Built with vanilla TypeScript and a lightweight custom engine, DiffMergy delivers sub-millisecond processing with zero network latency. The entire toolkit works on any modern browser across all operating systems, with no installation or setup needed.