Code & data
Regex tester
Test JavaScript regular expressions with match highlighting, flags, capture groups, and clear syntax errors. Evaluation runs with a time limit.
Free to useNo sign-upOn your device
Opening your workspace…
How to use it
- 01
Enter a JavaScript regex pattern without surrounding slashes.
- 02
Choose flags and add test text.
- 03
Run the pattern and inspect matches and capture groups.
A few useful answers
Which regex engine is used?
The tool uses your browser's JavaScript regular expression engine. Syntax can differ from PCRE or Python.
What happens if a pattern is too slow?
Evaluation runs in a worker with a timeout. A slow pattern is stopped and you can revise it without freezing the page.