A brief history of WHOIS
WHOIS has been the domain registration lookup protocol since 1982. It is a plain-text, unstructured protocol — every registrar implemented it slightly differently. Parsing WHOIS responses reliably requires a patchwork of per-registrar logic.
Enter RDAP
RDAP (Registration Data Access Protocol) is the modern replacement. It returns structured JSON, supports authentication for access tiers, and is operated over HTTPS. ICANN mandated RDAP support for all gTLD registries, and adoption is now widespread.
Key differences
- Format: WHOIS is free-text; RDAP is structured JSON.
- Reliability: RDAP fields are standardized — expiry date is always
expirationDate, not buried in varied text. - Privacy: RDAP supports tiered access. Public responses redact personal data by default (GDPR compliance).
- Speed: RDAP queries are generally faster and more reliable than legacy WHOIS servers.
How Dotily handles both
Dotily queries RDAP first. If the registry does not support RDAP or returns an error, we fall back to WHOIS automatically. This means near-100% coverage across all TLDs while maximizing data quality on registries that have made the switch.
Expiry dates, registrar info, and status codes are normalized into a consistent internal format regardless of which protocol provided the data.
What this means for you
Nothing changes on your end — Dotily abstracts the protocol layer. But it is worth knowing that WHOIS-based monitoring tools that have not added RDAP support will increasingly see degraded data quality as legacy WHOIS servers are retired.