IP Protocol Numbers API
The IANA "Assigned Internet Protocol Numbers" registry as an API — the 8-bit value carried in the IPv4 Protocol field (and IPv6 Next Header) that identifies the encapsulated protocol. Resolve any number to its protocol (e.g. 6 → TCP, 17 → UDP, 1 → ICMP, 47 → GRE, 50 → ESP, 58 → IPv6-ICMP, 89 → OSPF, 132 → SCTP), look up by keyword, search by name, or list all 151 assigned protocols — each with its keyword, full name, IPv6-extension-header flag and defining RFC. Ideal for packet/firewall tooling, network analysis, NetFlow/IPFIX decoders and protocol documentation. (Distinct from transport-layer service port numbers.)
api.oanor.com/ipprotocols-api
