RDAP API

RDAP (Registration Data Access Protocol) is the IETF standard that replaces the legacy WHOIS protocol. Where WHOIS returns unstructured free text over the unencrypted port 43 — formatted differently by every registry — RDAP returns structured JSON over HTTPS, supports internationalized data, and is mandated by ICANN for gTLD registries and operated by all five Regional Internet Registries. This API queries RDAP for you and flattens the complex, nested response into clean, stable JSON.

There are two GET endpoints. /rdap/v1/domain takes a domain query parameter and returns a flattened domain registration record (status, nameservers, registrar, dates, DNSSEC). /rdap/v1/ip takes an ip parameter — an IPv4 address, IPv6 address, or CIDR block — and returns a flattened network record with handle, name, type, country, CIDR, address range, and abuse contact. There is also a health check endpoint.

Yes, as a heuristic. When the authoritative registry reports a domain as not found, the API returns a 404 with available:true, which indicates the name is likely unregistered. If the TLD has no RDAP service at all, available is null so you can tell 'likely free' apart from 'unknown'. This is a strong signal for availability tools, but it is not a guarantee of registrability — always verify with a registrar before purchase.

Due to GDPR and similar privacy regulations, most gTLD registries redact personal registrant contact details (name, email, phone) at the source. This is a property of RDAP itself, not the API. You can still rely on non-personal fields — domain status flags, nameservers, registrar and IANA ID, and registration/expiration/last-changed dates — which remain fully populated. For IP lookups, organization and abuse-contact data is typically available.

The API runs on a global edge network and typically responds in under a second. Each query is routed through rdap.org, the IANA bootstrap redirector, which points to the authoritative registry (for domains) or Regional Internet Registry (for IPs). We follow that redirect and fetch the record straight from the source, so the data is authoritative rather than scraped or reconstructed from legacy WHOIS text.

Upstream conditions are mapped to clear HTTP status codes. A 400 means the supplied domain or IP was invalid. A 404 means the record was not found (with available:true for likely-unregistered domains). A 429 means the upstream RDAP service rate-limited the request, a 502 means the upstream returned an invalid or failed response, and a 504 means the upstream request timed out. This lets your client implement precise retry and backoff logic.

Yes. The ip parameter accepts an IPv4 address (e.g. 8.8.8.8), an IPv6 address, or a CIDR block (e.g. 8.8.8.0/24). The response includes the ip_version field along with the network's CIDR, start and end addresses, parent handle, registrant, and abuse contact — ideal for ASN enrichment, fraud scoring, and security tooling.