Thin vs Thick Registries: Why RDAP Needs a Second Hop
Why .com registrant data lives on registrar RDAP servers and how to merge registry + registrar responses.
thin registrythick registryRDAP referral
Definitions
Thin registries (e.g., .com) store technical domain data only. Registrant contacts live at the registrar. Thick registries return full contacts in one response.
Integration impact
A single registry query may be incomplete until you follow registrar links.
Merge strategy
- Follow links with rel=related.
- Fetch registrar RDAP and merge entities.
- Expose resultSource in your API.