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Regex Tester

Test regular expressions live, highlight matches, with flags and capture groups.

/ /
Flags:
  

Online regex tester

Regular expressions are powerful but easy to get wrong and hard to debug. This regex tester lets you build as you go: enter a pattern and test text, and every match is highlighted in real time with capture groups listed. It turns trial-and-error into something you can see.

How to use

  1. Type your pattern in the pattern field (without the / delimiters).
  2. Tick the flags you need (g, i, m…).
  3. Paste content into the test-text area; matches highlight live and groups are listed below.

Common use cases

  • Validate formats like email, phone or URL patterns.
  • Debug a regex that matches too little or too much.
  • Learn and experiment with regex syntax.

Frequently Asked Questions

Which regex flavor is this?

It uses the browser JavaScript RegExp engine, so the syntax matches JS. It is broadly compatible with PCRE, Python and others, though a few advanced features (like lookbehind support) may differ slightly.

Which flags are supported?

The common flags: g (global), i (ignore case), m (multiline), s (dotAll), u (unicode) and y (sticky). Just tick them.

Is my data uploaded?

No. The pattern and test text are matched locally in your browser and never uploaded.