Regex Tester
Type a pattern and some text to test it against — matches, capture groups, and a live replacement preview all update as you type. Matching runs using your browser's own JavaScript engine, so nothing you enter ever leaves this page.
Batch mode
Why test regex in the browser?
Regex testers are a classic "paste something you're actively working on" tool — often a log
line, a URL pattern, or a validation rule pulled straight out of production code. This tool
uses JavaScript's built-in RegExp engine,
the same one already running this page, so there's no reason for any of it to touch a
server.
Matching, capture groups, and the replacement preview are all recomputed on every keystroke using that local engine — check your browser's network tab while you use it.