Regular Expression Tester
Highlight regex matches, flags, groups and test replacements.
About the Regular Expression Tester
Test a regular expression against any text and see every match highlighted in place, with capture-group details. Toggle the global, case-insensitive, multiline, and dot-matches-all flags, and preview a replacement string with $1-style group references. Runs on the JavaScript regex engine in your browser.
Frequently asked questions
Which regex flavor does it use?
JavaScript (ECMAScript) regex — the same engine that runs in every browser and Node.js.
Can I test replacements?
Yes — enter a replacement pattern with $1, $2 group references and see the resulting string live.