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Regex Tester Online

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

Processing: in your browser (nothing uploaded)

About Regex Tester Online

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.

Why use Regex Tester

  • Runs 100% in your browser
  • No file uploads needed
  • Instant results
  • Private — data never leaves your device

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

Regex Tester runs entirely in your browser on FileToolsHub. Your text input is processed in this tab and is never uploaded to our servers.

That means passwords, tokens, personal notes, and documents you paste or load stay on your device. Clear the page or close the tab when you are finished on a shared computer.

You still need a network connection to load the page the first time. After that, the core processing for Regex Tester does not require sending your content to FileToolsHub.

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 does one focused job. For multi-step workflows, use the related tools below or the Text Tools hub.

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?

Yes. Regex Tester on FileToolsHub 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.

Does Regex Tester work on mobile?

Yes. Regex Tester works in modern mobile and desktop browsers. Large files may be slower on limited connections.

Can I use Regex Tester offline?

Once the page is loaded, most of Regex Tester runs locally. You need network access to open FileToolsHub the first time.

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