About This Tool

This regex tester helps developers write, test, and debug regular expressions with instant visual feedback. It uses JavaScript's native RegExp engine running entirely in your browser.

100% Client-Side

All pattern matching runs in your browser. No text or patterns are sent to any server. There is no backend, no database, and no tracking.

Features

Live match highlighting with alternating colors for adjacent matches. Capture group extraction with named group support. Replace mode with backreference substitution ($1, $<name>, $&). All JavaScript regex flags supported (g, i, m, s, u). Quick reference panel for common patterns.

Engine

This tool uses JavaScript's built-in RegExp engine. Patterns are compatible with JavaScript, TypeScript, Node.js, and most browsers. Some advanced features like lookbehind assertions require modern browsers (Chrome 62+, Firefox 78+, Safari 16.4+).

Contact

Questions or feedback? Reach us at the feedback link in the navigation.