Free browser tool

Regex Tester

Test JavaScript regular expressions and inspect match indexes in your browser.

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Regex tester

Test JavaScript regular expressions and inspect matches locally.

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Free regex tester

Use this tool to test search patterns for validation, log parsing, text cleanup, or JavaScript development.

Tool description

Test JavaScript regular expressions against sample text and inspect matched values and indexes.

Common uses

  • Test validation patterns before using them in code.
  • Debug log parsing, text extraction, or cleanup expressions.
  • Check JavaScript regex flags and match counts.

How to use Regex Tester

  1. 1. Enter a regex pattern and flags.
  2. 2. Paste the text you want to test.
  3. 3. Review each match and its index.

FAQs

Which regex flavor does this use?

It uses JavaScript regular expressions through the browser RegExp API.

Why does my regex error?

The pattern or flags may be invalid for JavaScript regular expressions.

Is my test text uploaded?

No. Matching runs locally in your browser.

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