Regular expression tester
Try a JavaScript pattern and check matches, groups, and indexes without blocking the interface.
Processed on this device. The files are not sent to a server.
How to use this tool
- Enter the pattern without bars, flags and text.
- Press Find Matches; cancel if you want to discard the job.
- Check the UTF-16 offsets and copy or download the JSON.
What you should know
Pattern up to 1,000 characters, text 100,000, 200 matches and g/i/m/s/u/y flags. Mandatory worker and time limit 750 ms. Long matches are truncated to 2,000 characters; up to 16 groups of 500 characters. Does not execute JavaScript code.
What happens with a very slow pattern?
The worker terminates after exceeding the time limit and displays an error. Simplify the pattern or reduce the text. It is not executed in the interface thread.