Regex Tester
Test regular expressions with live match highlighting, capture groups and common flags. Runs in your browser, nothing uploaded.
Test regular expressions online with live match highlighting, capture groups and flags (g, i, m, s). Paste your pattern and text, and matches light up as you type — the fastest way to debug a regex without running code.
Engine: ECMAScript (JavaScript) regular expressions — the same engine browsers and Node.js use.
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How to use the Regex Tester & Matcher
- Type your regex pattern and choose flags.
- Paste or type the test text.
- Matches, groups and positions appear live as you type.
Frequently asked questions
How do I test a regex online?
Enter your pattern and test string above; matches are highlighted live with zero setup.
What regex flavor does it use?
The JavaScript regex engine (ECMAScript), the same engine used by browsers and Node.js.
What do the flags g, i, m, s mean?
g = global, i = case-insensitive, m = multiline, s = dot matches newlines.
Can I see capture groups?
Yes — each match expands to show its numbered capture groups.