Regex tester
Matches 0
Flags gimu
Capture groups 0
Privacy Local only
Replace result
Regex testing runs in your browser. The pattern, test text, and replacement text are not sent to Heavens Help telemetry.
See examples
Check a pattern quickly
Paste a regular expression and test text to see matches, indexes, and captured groups.
Try JavaScript flags
Toggle global, ignore case, multiline, dotAll, unicode, and sticky flags while you refine a pattern.
Preview replacements
Type a replacement string and preview the result before using the regex in code.
About this helper
This regex tester uses the browser's JavaScript RegExp engine. It shows match positions, capture groups, named groups, and a replacement preview so you can refine a pattern before copying it into code. The pattern and test text stay in the browser.
Is my regex or test text uploaded?
No. Testing runs in your browser and telemetry does not include the pattern or text.
Which regex flavor does it use?
It uses JavaScript regular expressions, the same RegExp behavior available in modern browsers.
Why are only some matches shown?
The preview is capped to keep the page responsive when a pattern matches many times.