Developer

Regex tester

Test regular expressions against input text with live match highlighting and capture group display.

Pattern

Flags

g i m s

Test string

Matches

100% private. All processing happens locally in your browser — no files or data are ever sent to a server.

How to use Regex tester

01 Paste or type your input into the text field provided
02 The output generates instantly as you type
03 Click Copy to send the result straight to your clipboard

Frequently asked questions

Common questions about Regex tester.

Is Regex tester free to use?

Yes, Regex tester is completely free. No account, subscription, or payment is ever required — just open the page and start using it.

Does Regex tester upload my data to a server?

No. Regex tester runs entirely in your web browser using client-side JavaScript. Your files, text, and data never leave your device, making it 100% private.

Can I use Regex tester on my phone or tablet?

Yes. Regex tester is fully responsive and works on all modern smartphones, tablets, and desktop browsers without installing any app.

Does Regex tester work without an internet connection?

Yes. Once the page has loaded, Regex tester works fully offline — all processing is done locally in your browser.

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About Regex tester

Regular expressions (regex) are patterns used to match, search, validate, and transform text across virtually every programming language and many developer tools. The Regex Tester lets you write a pattern and test it against sample input text, with all matches highlighted in real time and any named or numbered capture groups displayed individually. It supports the full JavaScript regex syntax including case-insensitive (`i`), global (`g`), multiline (`m`), and dotAll (`s`) flags — making it easy to iterate quickly without leaving the browser.