Regex Tester & Validator

Extracts RFC 1034/2181-compliant fully qualified domain names delimited by pipe characters (the leading pipe is discarded via \K). Enforces a 253-character total length limit, 1-63 character labels that start with a letter (not a digit or hyphen), no trailing hyphens, and rejects double hyphens/punycode. Ideal for harvesting domains from pipe-delimited logs or data records.