Regex Tester
Test an ECMAScript regular expression and inspect every match, position, and capture group.
How to use
- Enter a pattern and supported flags, provide the test string, and run.
Capabilities and scope
A dedicated runner separates pattern, flags, and test text; it adds g for scanning even when omitted and lists up to 1,000 matches.
How it works
Flags are filtered to d,g,i,m,s,u,v,y and deduplicated; a global RegExp is used with matchAll to report ranges plus numbered and named captures.
Example
Applying (https?)://([^\s/]+) to URL text reports the full URL plus protocol and host captures.
Useful for
- Inspect JavaScript regex matches and capture groups in-browser
Before you use it
- Behavior follows the browser's ECMAScript RegExp support and output is capped at the first 1,000 matches.
Frequently asked questions
If I omit g, will only the first match appear?
No. The runner automatically adds g to the scan so all matches can be listed.