WHOIS, the 40-year-old protocol for looking up domain registration data, is being replaced by RDAP (Registration Data Access Protocol). Here's how to use it.
RDAP vs WHOIS
| Feature | WHOIS | RDAP |
|---|---|---|
| Format | Plain text | Structured JSON |
| Standard | Ad-hoc | IETF RFC 7480-7484 |
| Auth | None | Optional OAuth |
| Encoding | ASCII | UTF-8 |
| Discovery | Manual | Bootstrap via IANA |
How to Query RDAP
- Get the RDAP server URL from IANA bootstrap:
https://data.iana.org/rdap/dns.json
- Query the domain:
https://rdap.verisign.com/com/v1/domain/google.com
- Parse the JSON response for:
- Registration date
- Expiration date
- Registrar name
- Nameservers
- Status codes
- DNSSEC info
Bonus: Combine with DNS
Google DNS API gives you A, MX, NS, TXT records:
https://dns.google/resolve?name=stripe.com&type=MX
I built a WHOIS/RDAP + DNS lookup tool that combines both — free on Apify Store (search knotless_cadence whois).
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