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Regex Tester

Run pattern matching and replacement preview locally in your browser.

How to use

  1. Enter your regex pattern and choose flags like g, i, or m.
  2. Paste test text and click Run to inspect match positions and values.
  3. Set replacement text to preview transformed output before applying elsewhere.

FAQ

Why are no matches returned?

Check escaping, flags, and whether your pattern expects full-string vs partial matches.

Does this tool support capture groups in replacement?

Yes. You can use replacement tokens like $1, $2, etc., just like standard JavaScript replace.

Test regular expressions and preview replacements online

Use this free regex tester to check pattern matches, inspect match positions, try flags like g, i, and m, and preview replacements before using them in code, configs, or text-processing workflows. Everything runs locally in your browser.

Common regex tasks

Debug validation patterns

Test email, phone, ID, slug, and input-validation regex patterns before shipping them into forms or backend rules.

Inspect match positions quickly

See which substrings match and where they appear in the input, which helps when debugging greedy patterns or boundary conditions.

Preview find-and-replace safely

Try replacement strings such as $1 or $2 before applying bulk edits in editors, scripts, or migration jobs.

FAQ

Why are no matches returned?
Check escaping, flags, and whether your pattern expects full-string vs partial matches.
Does this tool support capture groups in replacement?
Yes. You can use replacement tokens like $1, $2, etc., just like standard JavaScript replace.
Does this regex tester run locally?
Yes. Pattern matching and replacement preview run in your browser, so your test input is not sent away by the tool itself.

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