Regex Tester
Test a regular expression against input text and see every match with its index and capture groups.
How it works
- 1
Enter your regex pattern in the Pattern option field and any flags (like g or i) in the Flags field.
- 2
Type or paste the string you want to test into the main input.
- 3
Every match is listed with its character index and any capture groups.
Questions
What flags are supported?
All standard JavaScript regex flags: g (global), i (case-insensitive), m (multiline), s (dotAll), u (unicode), and v (unicodeSets). The g flag is added automatically so all matches are returned.
What happens with an invalid pattern?
The tool shows the exact error message from the JavaScript regex engine so you can fix the pattern without guessing.
How are named capture groups shown?
Named groups appear in a 'Named' line below each match, alongside the positional group list.
Is the test string sent anywhere?
No. Regex matching uses the browser's built-in RegExp engine. Nothing leaves your device.
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