Regex Tester
Test JavaScript regular expressions, inspect matches and capture groups, and preview replacements locally.
Regex workspace
Test regular expressions and preview replacements locally.
Regex tested live
2 matches found locally.
Output
Matches
- Error 404: /accountat index 0
Groups: 404, /account
Named: {"path":"/account"}
- Error 500: /apiat index 40
Groups: 500, /api
Named: {"path":"/api"}
Questions
Which regex flavor does this use?
It uses the JavaScript RegExp engine available in your browser, so behavior matches modern web development environments.
Can it show capture groups?
Yes. Matches include their index, full matched value, numbered capture groups, and named capture groups when present.
Can I preview replacements?
Yes. Enter a replacement string with numbered or named capture references and copy the replaced output.
Does it run the regex on a server?
No. Patterns and test text are evaluated locally in your browser tab.
Does Utilumo upload my input?
No. This tool is designed for local browser processing and does not send your input to a server.
Do I need an account?
No. Utilumo tools are built to work without accounts or sign-in.