JavaScript Regex Tester
Test a JavaScript regular expression and inspect match text, positions and capture groups.
Runs in an isolated browser worker for at most one second and returns up to 200 matches.
How to use
Enter test text and a pattern without surrounding slashes.
Set JavaScript flags such as g or i.
Run the pattern and inspect up to 200 matches.
FAQ
How do I use this tool?
Enter test text and a pattern without surrounding slashes. Set JavaScript flags such as g or i. Run the pattern and inspect up to 200 matches.
Which regex flavor is used?
It uses the JavaScript RegExp implementation in your browser. Match positions are UTF-16 string offsets.
What happens with a very slow pattern?
The pattern runs in a separate browser worker. A one-second timeout terminates it; text is limited to 50,000 characters.
Are my inputs uploaded?
Tool inputs are processed in your browser. Advertising makes separate requests as described in the privacy policy.