Which regex flavour does it use?

It uses the JavaScript (ECMAScript) regular-expression engine, so patterns behave exactly as they would in JavaScript code.

What do the flags mean?

g matches globally, i ignores case, m makes ^ and $ match line breaks, s lets the dot match newlines, u enables full Unicode, and y makes matching sticky.

Developer Tools

Regex Tester

Test regular expressions against text and see every match live.

Free foreverRuns in your browserNo sign-up

About the Regex Tester

Regular expressions are compact patterns for finding and extracting text, used everywhere from validation to search-and-replace.

Type a pattern, choose flags such as global or case-insensitive, and paste your text to see every match and capture group update instantly.

This uses the same regular-expression engine as JavaScript, and everything runs in your browser so your text stays private.

Key features

Live matches as you type
All standard flags: g, i, m, s, u, y
Shows capture groups and match positions
Clear errors for invalid patterns

How to use

1Enter your regular expression and pick any flags.
2Paste the text to test against.
3Review the matches, positions and capture groups.

Frequently asked questions

Which regex flavour does it use?: It uses the JavaScript (ECMAScript) regular-expression engine, so patterns behave exactly as they would in JavaScript code.
What do the flags mean?: g matches globally, i ignores case, m makes ^ and $ match line breaks, s lets the dot match newlines, u enables full Unicode, and y makes matching sticky.