JSON formatter & validator
Format, beautify, validate, and minify JSON online. Pinpoint syntax errors by line and column, sort keys, and copy or download the result.
Regex tester
Test JavaScript regular expressions with live match highlighting, capture groups, flags, and replace preview.
/
/g
Highlighted matches
Use $1, $2… or $<name> for groups and $& for the whole match.
How to use Regex tester
Test JavaScript regular expressions live. Matches are highlighted as you type, with capture groups, named groups, and match positions listed below. Try a replacement pattern to preview the result.
- Flags: global, case-insensitive, multiline, dotAll, unicode, sticky
- Common patterns for emails, URLs, dates, and more
- Runaway patterns are stopped automatically so the page never freezes
Regex tester FAQs
Is Regex tester free?
Regex tester is a free online tool on ReallyUseful.Tools. No account is required.
Does Regex tester run in my browser?
Regex tester is designed to run in your browser where supported, so files can stay on your device instead of being uploaded to a server.
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