Regex Tester
Live match highlighting with a built-in cheat sheet
How to Use
The hardest part of writing regular expressions is that they look right but behave wrong. This tool highlights matches in real time as you type, so you can verify a pattern instantly instead of debugging it inside your code.
How to use: enter the pattern (no surrounding slashes needed), pick the flags you need (global, ignore case, multiline), paste your test text, and matches are highlighted immediately with capture groups listed. Common patterns can be copied from the cheat sheet and tweaked.
FAQ
Which language's regex syntax does this follow?
The tool uses your browser's JavaScript regex engine. Most languages share similar syntax, but advanced features like named groups or lookbehind may differ — re-verify when porting.
Why doesn't my pattern match across lines?
By default ^ and $ only match the start and end of the whole text. Enable the multiline (m) flag so they match line boundaries; use the dotAll (s) flag if you want . to match newlines.
Is my test text uploaded?
No. Matching runs entirely in your browser and the text is never sent anywhere.