Generates random strings that match a regular expression: literals and escapes, ., character classes and ranges, \d \w \s and their negations, groups, alternation, quantifiers and back-references. Unbounded quantifiers (* + {n,}) are capped by the repeat setting, characters come from the browser's cryptographic random source, and every result is re-tested against the real RegExp before it is shown. Lookaround, \p{…} and conditionals are not supported and are reported. Everything runs locally.