Regex Tester
Build and debug JavaScript regular expressions against your own text. Matches are highlighted inline, every match shows its index and capture groups, and a replace field previews the result. Toggle flags g/i/m/s/u/y with one click. Fully client-side, no uploads.
Frequently asked questions
Which regex flavor is used?
It uses the native JavaScript RegExp engine, so behavior matches what you get in browsers and Node.js.
Why do I need the g flag for highlighting?
Finding every occurrence requires the global flag; the tool adds g automatically for highlighting, while replace honors the flags you set.
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