Regular Expression Tester
Write a regex, paste test text, and see matches highlighted live with capture group breakdowns. Supports all JavaScript flags — instant feedback as you type.
Matching runs entirely in your browser — your text never leaves your device.
Matches
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How to use
- Type your regular expression and choose flags (g, i, m, s, u).
- Paste your test text.
- See live match highlighting and capture groups.
Frequently asked questions
Which regex flavor does this use?
JavaScript (ECMAScript) regular expressions, since matching runs in your browser. Most syntax is identical to PCRE; lookbehind and named groups are fully supported.
How do I see capture groups?
Every match expands to show its numbered and named capture groups, so debugging complex patterns takes seconds instead of guesswork.
Why is my regex not matching?
Common culprits: forgetting the g flag for multiple matches, unescaped special characters like . or (, or greedy .* swallowing too much. The live highlight makes each fix visible instantly.