domain_sanity

https://github.com/msuliq/domain_sanity

A small, fast Ruby gem for validating and inspecting domain names the way a certificate authority has to: RFC 1035 label rules, IDN/punycode round-tripping, Public Suffix List and TLD checks, CA/Browser Forum aware wildcard rules, plus IP address, private/reserved range, and reverse-zone detection. Two runtime dependencies, both pure Ruby.