WhoisThisDomain - Domain name lookup tool that allows you to get information about domain registration from WHOIS server.
WhoisAPI - WhoisAPI is the premier provider of freshly parsed whois data for domain names and IP addresses...
Whoisology - Connected database of whois records and whois history
GetWhoisData - Whois Database Download using FTP. Instant Access. Daily Update. No download Limits. supports 13 TLDs and 677 gTLDs. Country wise database
Bulk Whois API - Bulk Whois API is a provider of parsed WHOIS data in JSON with simple API, competitive pricing, top notch support, and more.
Oribi - Analytics for marketing & product teams