This tool uses JavaScript's built-in RegExp engine, which supports ECMAScript regex syntax. This includes features like named capture groups, lookaheads, lookbehinds, Unicode property escapes, and the dotAll (s) flag.

g (global) finds all matches instead of just the first one. i (case-insensitive) ignores letter case. m (multiline) makes ^ and $ match line boundaries. s (dotAll) makes . match newline characters. u (unicode) enables full Unicode matching and proper surrogate pair handling.

Absolutely. This regex tester runs entirely in your browser using JavaScript's native RegExp engine. No text or patterns are sent to any server. Your data never leaves your device.

Use named capture group syntax in your regex, for example: a pattern like (?P-year-), (?P-month-), (?P-day-) separated by hyphens will create named groups. The tool displays both named and numbered capture groups for each match.