Regex Tester
Runs locally
Enter a pattern, flags and test string to see matches, capturing groups and match count instantly.
Your data is processed locally in your browser and is not uploaded.
Learn more about this tool⌄
How it works
The pattern runs against your test string using the browser's native RegExp engine, entirely client-side.
Common use cases
- Debugging validation patterns
- Learning regex
- Extracting data with capturing groups
Frequently asked questions
- Can a bad pattern freeze the page?
- Input length and pattern complexity are limited to reduce the risk of catastrophic backtracking, but very pathological patterns can still be slow in any regex engine.