Coldwast

Regex tester

Type a regular expression and some test text to see the matches and capture groups update live. It uses your browser's own JavaScript regex engine, so nothing is sent anywhere.

Pattern

Flags

Test string

Common flags

g - global, find all matches
i - case-insensitive
m - multiline (^ and $ match line breaks)
s - dotall (. matches newlines)
u - unicode
y - sticky

How it works

The tester compiles your pattern with the JavaScript RegExp engine and runs it against the test string. Matches are highlighted and each capture group is listed. Because it runs in your browser, large or private text never leaves your device.

This uses the JavaScript regex flavour (ECMAScript). Some syntax from PCRE, Python or other engines can behave differently.