ip-fast.com
IP address, country and city

WHOIS domain name lookup.
IP2WHOIS Information Lookup API is a free Development API that requires apiKey authentication, is served over HTTPS and has unconfirmed CORS support.
WHOIS domain name lookup service to search public WHOIS database for domain name registration information and hosted domain information
Details from ip2whois.com.

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Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
IP address, country and city
Geographic location of an IP address or any domain name along with some other useful information
Agent-first directory of skills, MCP servers, tools, protocols and APIs as JSON, markdown, llms.txt
The IP2WHOIS Information Lookup API is provided by ip2whois.com (ip2whois.com). WHOIS domain name lookup service to search public WHOIS database for domain name registration information and hosted domain information
Yes. The IP2WHOIS Information Lookup API is listed in the Development category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
Yes. The IP2WHOIS Information Lookup API uses apiKey authentication, so you need to register for credentials before making requests.
CORS support for the IP2WHOIS Information Lookup API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The IP2WHOIS Information Lookup API is served over HTTPS, so it's safe to use in production.