Regex Tester

Test JavaScript regular expressions with live highlighting, capture groups, flags, a replace preview and a library of common patterns.

How to use Regex Tester

1. Type your pattern and choose flags.
2. Paste test text to see matches highlighted.
3. Use the Replace box to preview substitutions.

Frequently asked questions

Which regex flavor is used?

JavaScript (ECMAScript) regular expressions, including named groups and Unicode properties.

How do I match an email address?

Click the "Email" pattern in the library to insert a ready-made expression.