Choose a registry data source according to the question you need to answer. Registration information, live availability, a registrar's own portfolio and a projected drop are different questions. A single lookup cannot establish ownership authority, transfer readiness, sale terms and availability at once.
Match the task to the source
| Task | Appropriate starting point | Important limit |
|---|---|---|
| Inspect public registration information | DomainSabre's UK lookup, which queries Nominet RDAP directly from your browser, or Nominet's own client | Public fields may be limited; a record is not evidence of the seller's authority |
| Determine whether a registration can be attempted | A registrar's availability service, using the applicable registry checking mechanism | A successful check does not reserve a domain |
| Review a registrar's own registration records | Its authorised management tools and applicable portfolio-data service | Access and field scope depend on authority and environment |
| Investigate expected drops | Search the published UK drop list and read the official source specification | Some names may be recovered; a list is an observation, not an allocation |
| Plan a transfer | Registrar instructions plus relevant current domain state | Registration data alone does not prove that a transfer is authorised or unblocked |
For Dragon integrations, Nominet's availability guidance identifies EPP checks, drop lists and the unavailable-names report as different mechanisms. Their purposes overlap, but their access conditions and freshness are not interchangeable.
Current services and scheduled replacements
At the source review on 3 November 2026, the future .UK configuration continued to distinguish the current legacy platform from the scheduled RSP platform. Do not assume that a new documentation page means an old production dependency has already stopped working.
Nominet's preparation guidance maps legacy DAC, WHOIS/WHOIS2 and list-API dependencies to their future alternatives. Its RDAP migration guidance describes the scheduled retirement of the .UK WHOIS protocol. Review the precise interface used by your application: a retail website calling something “WHOIS” may be presenting data obtained through a different protocol.
An integration inventory should therefore record the actual endpoint or protocol, the information consumed, the failure behaviour and the scheduled replacement. Include scripts used by support or finance teams; an old nightly report can be as operationally important as the main registration application.
Public RDAP and credentialled RDAP
Public RDAP provides structured registration information under the service's disclosure and usage rules. DomainSabre's UK WHOIS lookup submits one deliberate browser request to the official endpoint; opening a prefilled link does not query it. It does not centralise queries through a server proxy, cache registry responses or harvest contact details. Missing fields, no record, rate limits and network failures are distinct outcomes, and none is a registration guarantee. Credentialled RDAP adds authenticated access to data the caller is permitted to receive. Authentication does not make the resulting data an unrestricted marketing dataset.
The official credentialled RDAP guide describes the replacement of the legacy REST/SOAP list APIs. It says production .UK support begins with transition; it also distinguishes testbed settings from production. The documented reduced portfolio response and its pagination should not be assumed to contain every field of a full domain response.
When designing a migration, compare the fields actually returned against the fields your report needs. Record whether a date is registration, expiry or last change. Keep the record's event timestamp separate from the time you retrieved it. Where a query is paginated, establish whether all pages were retrieved before concluding that a name is missing.
Availability is time-sensitive
An availability result tells you about a particular check, not a future entitlement. Between checking and registering, another request may succeed, a state may change or a policy condition may become relevant. For a buyer, the practical consequence is to distinguish “the provider showed it as available” from “the registry accepted the registration”.
A failed response has different meanings. A timeout, authentication failure, rate limit, malformed request and a valid “not found” answer should not all become one empty field in a report. If the result is unavailable, preserve that state and the time of the attempt; do not turn it into a claim that the name is free.
Drop lists and unavailable-names reports
Nominet's official drop-list page links the downloadable files and platform specification. A projected drop deserves a state and freshness check. See the drop-list interpretation guide for fields, UTC dates and illustrative records, and the lifecycle guide for recovery and deletion concepts.
The unavailable-names report has different access and reuse restrictions. Nominet limits it to registrars accredited for the relevant registry and prohibits publication. A public explanation of the service is not permission to mirror its contents or sell a copy. DomainSabre's drop search uses the public daily source and displays its freshness and coverage. It does not reproduce the restricted report, scrape another provider's inventory or enrich the feed with bulk registration queries. Source publication, import and check times remain separate. A last-known-good list can be displayed with a warning while new reminders and sending are paused; a failed or incomplete import is not evidence that names were withdrawn.
Record uncertainty as part of the evidence
Fictional investigation example: a researcher sees a successful public record yesterday, a timeout this morning and a registrar dashboard showing an older expiry date. Those observations do not establish that the domain disappeared overnight. The researcher should retain each source and time, identify which data is cached, and obtain a successful current response or provider clarification before making a transfer decision.
| Evidence state | Accurate description | Conclusion to avoid |
|---|---|---|
| Successful observation | “This source returned this value at this time” | “The value will remain true until the planned transaction” |
| Stale observation | “The latest successful observation is dated…” | “Rechecking the page refreshed the underlying data” |
| Query failure | “The query did not establish the state” | “No result means no registration” |
| Restricted access | “This caller is not authorised to view that field” | “The underlying field does not exist” |
| Conflicting records | “These sources disagree; reconciliation is outstanding” | “The most convenient value is confirmed” |
This evidence discipline also applies to domain transfers. For technical migration, use the environment guide and EPP preparation guide, with the transition hub for current applicability.