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Regex Tester

Write a pattern, see matches highlighted live — with capture groups and all the flags.

🔒 Everything runs in your browser — patterns and text are never sent anywhere

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Flags cheat-sheet

g finds every match instead of stopping at the first · i ignores letter case · m makes ^ and $ match each line's start and end · s lets the dot match newlines · u enables full Unicode mode (needed for emoji ranges and scripts like Bangla). The tester uses your browser's native JavaScript regex engine — exactly what runs in Node.js and front-end code, so what matches here matches in production.

FAQ

Which regex flavor is this?
JavaScript (ECMAScript) — the same engine as Node.js and browsers. Most patterns port directly to Python or PHP, but a few features (like lookbehind support and named groups syntax) can differ.
Why does my pattern show an error?
The pattern isn't valid regex syntax — common culprits are unescaped special characters ( ) [ ] . * + ? and unbalanced brackets. The exact engine error is shown to help you fix it.
What are capture groups?
Parts of the pattern wrapped in parentheses — each match lists its groups separately, which is how you extract just the piece you need (like the domain out of an email).

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