Developer Tools
Regex Tester
Test regular expressions against sample text with live highlights.
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About this tool
Type a regex, pick flags, and watch every match light up in your test text. See capture groups, named groups, match indices, and any parse errors immediately. Pure JavaScript regex — what you see is exactly how RegExp behaves in browsers and Node.
Frequently asked questions
Which regex flavor is supported?
ECMAScript / JavaScript RegExp — the same engine your browser and Node use. Lookbehind, named groups, and unicode flags are all supported in modern browsers.
Can I see capture groups?
Yes. After running the regex you'll see every numbered and named group for each match, with the group's start/end index in the source text.
Is there a syntax cheat sheet?
Yes — see the Regex Library tool for ready-made patterns and a quick reference.