Method comparison
RDAP vs WHOIS vs DNS vs a registrar search
RDAP and WHOIS retrieve registration data; DNS answers whether records resolve; a registrar checkout determines whether that seller can register the name for you and at what price. They are related checks, not interchangeable proof.
| Method | Best question | Main limit |
|---|---|---|
| RDAP | Does the registration service have a structured record for this exact name? | A no-match does not guarantee sale; public fields may be redacted. |
| Port-43 WHOIS | Can a legacy registry return a text registration record? | Unstructured, inconsistently available and susceptible to throttling. |
| DNS | Does the queried name currently publish DNS records? | A registered domain can have no public DNS; absence is not availability. |
| Registrar search | Can this registrar sell the name now, under which rules and price? | Commercial result and price are specific to that registrar and moment. |
SeekDom's method
SeekDom resolves RDAP endpoints from IANA bootstrap data and only falls back to WHOIS when no RDAP service is known. It does not use a missing DNS answer as availability proof. Results are registered, no registration found, or not checked.
Protocol context
ICANN describes RDAP as the replacement for WHOIS. Since 28 January 2025, gTLD registries and registrars generally are no longer required to provide WHOIS, with limited exceptions. Country-code registries follow their own policies and can expose different services.
Primary sources
- ICANN: Registration Data Access Protocol
- ICANN Lookup FAQ
- IANA RDAP bootstrap registry
- RFC 9082: RDAP query format
Reviewed 10 September 2026. See the human RDAP and WHOIS guide or run a lookup.