Regex Tester
Test and debug regular expressions live.
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About the Regex Tester
Test regular expressions free with live match highlighting. Type a pattern, set flags (g, i, m, s), paste sample text, and see every match highlighted instantly with its capture groups listed — no more guess-and-run debugging. It uses JavaScript's native regex engine, so what works here works in your Node.js and browser code exactly the same way.
How to use the Regex Tester
- 01Enter your regular expression and choose flags.
- 02Paste a test string.
- 03See matches highlighted and listed with their capture groups.
Frequently asked questions
Which regex flavor is this?
It uses JavaScript's regular expression engine, the same one that runs in every browser.
What do the flags mean?
g = global (all matches), i = case-insensitive, m = multiline, s = dot matches newlines.
Why isn't my regex matching?
Most often: unescaped special characters (. + ? ( ) [ ]), a missing g flag when expecting multiple matches, or greedy vs lazy quantifier confusion (.* vs .*?).