Regex Tester & Cheat Sheet

Test regex in real time

Type a pattern and matches in the text below are highlighted instantly. The fastest way to learn regex is to test against real strings instead of guessing in your head.

A ready-to-use example

Grab just the domain from emails:

Pattern:  @([a-z0-9.-]+)
Input:    hi@toolhub.com, ask@example.org
Matches:  @toolhub.com, @example.org

Common building blocks:

• \d digit, \w letter/digit/underscore, \s whitespace
• + one or more, * zero or more, ? zero or one
• ^ start of line, $ end of line, . any single char

Don't forget the flags

• g: find all matches instead of stopping at the first
• i: case-insensitive
• m: apply ^ and $ per line in multi-line text

If "only the first one matches," you're almost always missing the g flag.

Your pattern and text are processed only in the browser. For a library of common patterns, see the regex tester & cheatsheet.