Developer · free local utility
Compile a JavaScript pattern against sample text and inspect match indexes, capture groups, and named groups.
Enter the pattern without surrounding slashes, choose JavaScript flags, and paste the text to test.
The syntax follows the JavaScript engine in your browser. It is not a PCRE, RE2, Python, or .NET compatibility checker.
Always verify the result in the system where you will use it. The page intentionally avoids accounts, uploads, and claims that go beyond the calculation it performs.
No. Enter only the pattern body. Flags go in the separate flags field.
The tool accepts JavaScript flags supported by modern browsers, including d, g, i, m, s, u, v, and y.
The runner advances after an empty match and limits output to 200 matches to avoid an infinite result loop.