Why we built our own WHOIS dataset
WhoisToolkit is a domain data service that does its own collection. We gather registry zone files and RDAP records every day and serve the result through one API.
The problem with resold data
Most WHOIS APIs sell access to a dataset someone else collected. That works until you need to know how fresh a record is, where a field came from, or why a domain registered yesterday isn't there yet. The answer is usually on the other side of a supplier you can't see.
The underlying data is public: registries publish zone files, and registries and registrars run RDAP services. Collecting it well is mostly patience: hundreds of millions of names, and servers that each answer a little differently.
So we collect it ourselves, from the registries and registrars that publish it, and keep the original response alongside the fields we parse from it.
How the data is collected
Where each part of a record comes from, and what to expect from it.
Zone files tell us which domains exist
We download each registry's zone file through ICANN's Centralized Zone Data Service, every day. It lists the domains in that TLD and the nameservers they use.
RDAP provides the registration details
Dates, status codes and the registrar come from the registry's own RDAP service. Contact details come from the registrar's RDAP service, which we reach through the registry's referral link.
Some contacts are redacted
Many registrars withhold registrant details. When they do, the record is marked as privacy protected and contains only what the registrar published.
History starts when we started
Records go back to when our own collection began, plus the dates that registries report themselves, such as the original registration date.
Records can be incomplete or out of date
A record reflects what the registry and registrar published when we last fetched it. If something looks wrong, let us know and we'll check it against the source.
Spotted a record that looks wrong, or a TLD you think we're missing? Tell us and we'll check it against the source.