Regex Tester
Build and debug regular expressions with live match highlighting, capture groups and a replace preview.
\d digit · \w word char · \s whitespace. any char · ^ start · $ end* 0+ · + 1+ · ? optional{2,5} 2–5 times · \b word boundary[a-z] class · [^x] not x(…) group · (?<n>…) named · | orFree online regex tester
The Ajenza Regex Tester runs your regular expression against test text using the browser's own JavaScript RegExp engine and highlights every match as you type. It lists each match with its numbered and named capture groups, counts the matches, and previews a find-and-replace using $1, $<name> and other substitutions. All six JavaScript flags are supported. Nothing is uploaded — your pattern and text stay on your device.
Is it free?
Yes — completely free, with no sign-up, download or watermark.
Which regex flavour is this?
JavaScript (ECMAScript). Syntax like named groups (?<name>…) and lookbehind works where your browser supports it.
Is my text uploaded?
No — everything runs in your browser.
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