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Regex Tester

Test JavaScript regular expressions with live match highlighting, capture groups and flags. Free online regex tester.

Processed on your device Works offline Free, no sign-up
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How to use Regex Tester

  1. Type a pattern and choose flags.
  2. Paste test text.
  3. Matches and capture groups appear instantly.

Frequently asked questions

Which regex flavor is used?

JavaScript (ECMAScript), the same as in browsers and Node.js.

Is Regex Tester free?

Yes. Regex Tester is completely free, with no sign-up, no watermark and no usage limits.

Is my data uploaded to a server?

No. Regex Tester runs entirely in your browser. Your files and text never leave your device.

Does it work offline?

Yes. After Red Cat Tools has loaded once, this tool keeps working without an internet connection. You can also install Red Cat Tools as an app.

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