Regex Tester
Test regular expressions in real-time.
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How to use
How to use Regex Tester
Test patterns against sample strings before you ship them to production.
- 01
Enter your regular expression and flags.
- 02
Paste test strings in the input area.
- 03
Inspect matches, groups, and highlights in real time.
Common questions
Which regex flavor?
JavaScript RegExp syntax — what runs in browsers and Node. Lookaheads and named groups depend on your pattern.
Why no match?
Check flags (g, i, m), escaping special characters, and whether anchors ^ $ are used correctly.
ReDoS risk?
Pathological patterns can hang on huge inputs. Test with reasonable sample sizes.
Runs in your browser · Your input is never uploaded · Free with no account