Registration Data Access Protocol (RDAP) is a successor to WHOIS protocol.

Pros

JSON format Supports HTTPS Unicode support Uniform schema unlike whois which differs from registry to registry

Cons

Rate limiting Authentication Tiered (restricted?) access

Bootstrap URLs

DNS

curl -Ls https://data.iana.org/rdap/dns.json

RIRs

curl -Ls https://data.iana.org/rdap/ip.json

ccTLDs

curl -Ls https://data.iana.org/rdap/cctld.json

Examples

Querying using web browser

For querying using web browser, use https://client.rdap.org/

Querying using CLI

Domain

curl -Ls https://rdap.org/domain/example.in | jq .

ASN

curl -Ls https://rdap.org/autnum/16276 | jq .

IP Address

curl -Ls https://rdap.org/ip/1.1.1.1 | jq .

Entity

curl -Ls https://rdap.org/entity/APNIC | jq .