Test and debug regular expressions instantly

Writing regular expressions can be difficult when a pattern does not match the text you expect. Use this online regex tester to experiment with patterns and test them against real strings without installing another application.

Enter a regex pattern and test data to quickly see matches, identify capture groups, and understand how your expression behaves.

Useful for developers and programmers

• Testing email, URL, username, and phone number patterns
• Debugging complex regular expressions before deployment
• Checking capture groups and matched text
• Experimenting with regex flags and pattern variations
• Learning how regular expression syntax behaves
• Validating patterns for JavaScript and web development

What is a regular expression?

A regular expression, commonly called a regex or regexp, is a pattern used to search, match, validate, and manipulate text. Developers use regular expressions for tasks such as finding specific strings, validating input, extracting information, and replacing matching text.

Because regex syntax can become difficult to read, testing a pattern against sample text is one of the easiest ways to understand whether it behaves as expected.

Why use an online regex tester?