Make every match make sense..
Try JavaScript regular expressions in an isolated worker with a 250 ms execution budget.
Regex lab
01 / INPUT TO OUTPUTA clearer view starts here.
Your result will appear here.
Same device. A little less friction.
Less context switching.
More getting it done.
One focused workbench. Six useful tools.
Your data stays in session memory until you clear it.
Bring your input
Paste test data or open a local UTF-8 file.
Make it make sense
Choose the rules. Run the tool. Inspect the result.
Take your work with you
Copy or download only when you’re ready.
At this desk: Regex lab
Enter a pattern without enclosing slashes. Set JavaScript flags and run explicitly. Captures, named groups, and UTF-16 offsets appear in the result.
The worker is terminated after 250 ms of evaluation wall time. Cancel stops it immediately; startup has a separate 10 s limit. A timeout is not proof that a pattern is safe or unsafe elsewhere.
5 MiB text, 10,000-byte pattern, 1,000 matches. Match/group strings and preview are bounded; truncation is disclosed. Browser regex syntax varies; unsupported flags fail visibly.
Clear session removes application references, not downloaded files or browser/OS memory. Ordinary application asset requests still reach the host. There is no analytics, content persistence, or processing service.