Regex Tester
Test a JavaScript regular expression against input and highlight every match.
Private by design. Every tool runs 100% in your browser — your code, text, and tokens never leave your device. Nothing is uploaded or stored.
Matches
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Frequently Asked Questions
Why does my regex match nothing?
Common causes: forgetting to escape . or /, wrong flags (missing g or i), or anchoring with ^ $ when you meant a partial match. The tester highlights every match so you can see what the engine sees.
What do the flags mean?
g = global (all matches), i = case-insensitive, m = multiline anchors. Picking the wrong set is the most frequent regex bug.
Is JavaScript regex enough?
For most web text it is. Lookbehind and named groups are supported in modern engines; very old targets may need a different flavor.