Regex Tester

Test regular expressions with live matches and flag controls.

Flags

Valid regex3 matches
user_123
Start index: 0
admin_456
Start index: 37
guest_12
Start index: 72

Regex Quick Tips

  • Use \\d for digits, \\w for word chars, and \\s for whitespace.
  • Add i for case-insensitive matching and m for line-based anchors.
  • All matching happens locally in your browser for privacy and speed.

FAQ

Which regex flags are supported?

The Regex Tester supports common JavaScript flags including global, ignore-case, multiline, and dotall.

Can I see match positions?

Yes. The tool lists each match and its start index in the input text.

Does this run in the browser?

Yes. Pattern testing runs locally in your browser using JavaScript regex behavior.

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