Free Online Regex Tester
Build and test regular expressions with real-time match highlighting. See matched groups, test against sample text, and debug patterns instantly.
How to Use the Regex Tester
1
Enter your regex pattern in the pattern input.
2
Set flags (g, i, m, etc.) as needed.
3
Enter test text in the text area.
4
Matches are highlighted in real time.
Frequently Asked Questions
What regex flavor does this use?
It uses JavaScript's built-in RegExp engine, which supports most standard regex features including lookaheads, character classes, and quantifiers.
Can I see capture groups?
Yes. Matched capture groups are displayed separately so you can verify your grouping patterns.
What flags are supported?
Global (g), case-insensitive (i), multiline (m), dotAll (s), and unicode (u) flags are all supported.