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.
WhoisThisDomain - Domain name lookup tool that allows you to get information about domain registration from WHOIS server.
Whoisology - Connected database of whois records and whois history
CubDomain - CubDomain.com is the site to check website's statistics, Information, Whois Record, Hosting...
WebCargo - Optimize your workflow by offloading it to us. Useful API's with seamless integration that scale to your needs.
Hostlogr.com - Hostlogr.