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Regex Tester

Test regular expressions online against sample text and view matches — JavaScript RegExp in your browser.

Processing: runs in your browser, nothing uploaded

✓ Free to use✓ No sign-up needed✓ Nothing to install

About Regex Tester

Regex Tester online runs JavaScript regular expressions against sample text with live matches — ideal when you need to test a pattern before shipping form validation or log scrapers.

Paste your pattern and flags, paste sample input, and review match groups.

JS RegExp differs from Python/PCRE in lookbehind and unicode details, so keep patterns small and test edge cases.

Everything runs in your browser — nothing uploaded.

How to use Regex Tester

  1. 1

    Paste or type your input in the editor.

  2. 2

    Click Process to transform instantly.

  3. 3

    Copy the result with one click.

Use cases

  • Test form-validation patterns before shipping
  • Debug log-scraping regular expressions
  • Compare match groups with live sample text
  • Practice JavaScript RegExp flags privately

Privacy

Runs entirely in your browser — your text input is not uploaded.

Limitations

  • Regex Tester depends on your browser. Very large inputs may slow or freeze older devices; try a smaller sample if the tab becomes unresponsive.
  • Regex Tester uses JavaScript RegExp syntax — not PCRE, Python, or .NET flavors.

Regex Tester FAQ

Which regex flavor?

JavaScript RegExp with flags such as g, i, and m.

Is my text uploaded?

No. Matching runs entirely in your browser.

Which flavor?

JavaScript RegExp syntax with custom flags (g, i, m, etc.).

Invalid pattern?

You'll get a clear syntax error message.

Is Regex Tester free on FileToolsHub?

Yes. Regex Tester is free for everyday use with no account required for standard jobs.

How do I use Regex Tester?

Paste or type your input in the editor. Click Process to transform instantly. Copy the result with one click.

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