Which regex flavor does this use?

JavaScript's native RegExp - the same engine your browser and Node.js both use.

Why does it always search globally, even without the g flag?

So "how many matches" is always answerable - without it, only the first match would ever be found.

No - matching runs entirely in your browser.

Test a regular expression against sample text and see every match highlighted.

Pattern

i m s

Test string

5 matches

Order #123 shipped on 2024-06-15, tracking 4567.

Files never leave your device - matching runs entirely in your browser.

1
Enter a pattern

A regular expression, with optional i/m/s flags.
2
Paste test text

Any text you want to test the pattern against.
3
See every match highlighted

Along with each match's position and capture groups.

Which regex flavor does this use?: JavaScript's native RegExp - the same engine your browser and Node.js both use.
Why does it always search globally, even without the g flag?: So "how many matches" is always answerable - without it, only the first match would ever be found.
Does this tool send my text anywhere?: No - matching runs entirely in your browser.