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Regex Tester

Developer

Free online regex tester with live match highlighting, capture group display, and pattern explanations. Test regular expressions against any text instantly in your browser.

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Pattern2 matches
//g
Test string
Highlighted
Email Ada at [email protected] or Grace at [email protected] to confirm.
No match: just plain text on this line.
Matches

Writing a regular expression rarely works on the first try, and the real test isn't whether a pattern looks right, it's whether it actually matches the specific strings it's supposed to and rejects the ones it isn't, edge cases included, something that's nearly impossible to verify just by reading the pattern itself. This tool runs a regex against real sample text, highlighting every match live as the pattern changes and displaying each capture group separately, so the actual matching behavior stays visible while a pattern is still being refined rather than only after it ships in actual code.

See more about the Regex Tester

Useful for iterating on a pattern against a handful of test strings until it correctly separates the ones that should match from the ones that shouldn't, checking exactly what a capture group pulls out of a match, or confirming a regex handles an edge case before it goes into production code.

Key features

  • Clean interface
  • Fast processing
  • No signup required
  • Works offline

Quick answers for Regex Tester

What is the Regex Tester?
The Regex Tester is a free online playground for regular expressions. Type a pattern, paste the text to match against, and see matches and capture groups highlighted live with flag support (g, i, m, s, u).
Which regex flavor does the Regex Tester use?
The Regex Tester uses JavaScript (ECMAScript) regex, which is the flavor you ship in a web app, Node.js script, or browser-side code. Named groups, lookbehinds, and unicode property escapes are all supported in modern browsers.
Can I test multiline regex patterns?
Yes. Toggle the m flag to make ^ and $ match line boundaries, or s to let . match newlines. The Regex Tester shows exactly which flags are active.
Does the Regex Tester explain my pattern?
Yes. The Regex Tester breaks down each token in the pattern - anchors, character classes, quantifiers, groups - into plain English so you can verify what it actually matches.
Is my regex and test text private?
Yes. Everything in the Regex Tester runs in your browser. Nothing is sent to any server, so you can test patterns against confidential logs and data.