Regex Tester
Test regular expressions with live highlighting and match information
Regular Expression
Test String
Results
Regular expressions (regex) are patterns used to match, search, and validate text - powerful but notoriously easy to get subtly wrong. This tool lets you write a regex pattern and test it live against sample text, highlighting exactly what it matches so you can debug and refine your pattern before using it in real code.
Frequently asked questions
It generally follows JavaScript's regex syntax, which is very close to what's used in most modern languages, though some advanced features vary slightly between languages (like Python or PHP) - test your final pattern in your actual target environment for anything highly specialized.
Yes - common flags like case-insensitive (i) and global (g) matching can be toggled to see how they change what the pattern matches.
The live highlighting on your sample text shows you exactly what matches, which is often the fastest way to understand and debug a pattern's actual behavior.