Test a JavaScript regular expression against sample text with live highlighting. Capture groups, match positions and flags are all shown, and nothing is uploaded. 100% Local
How to Use the Regex Tester
Enter a pattern, optional flags (g, i, m, s, u, y) and a test string. Matches are highlighted and listed with their index and captured groups.
Notes
Patterns use JavaScript regular-expression syntax.
Invalid patterns are reported immediately instead of throwing.
Global matching is capped at 10,000 matches to stay responsive.
Features
Live match highlighting in the test string
Capture groups and match positions listed
Support for the common JavaScript flags
All processing runs locally in your browser. Your input is not uploaded to any server.
A match here is a tool result — always test your pattern against real edge cases before relying on it.