Section 03 · RDDS

RDDS and RDAP: the registration data system behind every lookup

Registration Data Directory Services, or RDDS, is ICANN's umbrella term for the services that give access to domain registration data. In practice that now means RDAP, the Registration Data Access Protocol, which returns structured, machine-readable responses and supports differentiated access, so different requesters can see different fields.

This section is for readers who want the plumbing explained: developers building lookups, security teams triaging phishing domains, agencies managing dozens of client names, and owners who simply want to know where their data goes.

We cover how redaction is applied under ICANN's Registration Data Policy, how RDAP responses are structured, how registry and registrar data differ, and how lawful requests for nonpublic data work through registrars and ICANN's Registration Data Request Service. We won't explain how to get at registration data you aren't authorized to see. The aim is to understand the system well enough to use it properly, and to spot when someone's claims about it don't add up.