Test and debug regular expressions with real-time match highlighting. Runs entirely in your browser.

Try it

How it works

The tool uses the browser’s native RegExp engine — the same one that runs in Node.js:

const re = new RegExp(pattern, flags);
const matches = [...text.matchAll(re)];

Each match is wrapped in a <mark> tag for highlighting. That’s it — no libraries, no server.

Quick regex cheat sheet

Pattern	Matches	Example
\d+	One or more digits	123, 42
\w+	Word characters	hello, foo_bar
[a-z]+	Lowercase letters	abc, hello
^.+$	Entire line (with m flag)	Any non-empty line
\b\w{4}\b	Exactly 4-letter words	this, that
https?://\S+	URLs	https://example.com
[\w.]+@[\w.]+	Simple email pattern	user@example.com