WhoAPI is described as 'Comprehensive API that delivers parsed Whois results, domain availability information, website screenshots, PageRank, Alexa rank, and other domain data'. There are more than 10 alternatives to WhoAPI, not only websites but also apps for a variety of platforms, including Windows, Linux, Mac and Android. The best alternative is DomainTools, which is free. Other great sites and apps similar to WhoAPI are WebCargo (Paid), JsonWhois.io (Freemium), WhoisAPI (Freemium) and CubDomain (Free).
JsonWhois is the leading cloud hosted Whois API. The service serves WHOIS records for domains and IP addresses through a fully RESTful API. Additionally, the service offers IP geolocation and URL to screenshot services. Free usage per month!.
WhoisAPI is the premier provider of freshly parsed whois data for domain names and IP addresses, also providing IP to geolocation, HTML to PDF, and domain availability RESTful HTTP APIs. Billing is performed on a pay as you go basis, free monthly use.
Bulk Whois API is a provider of parsed WHOIS data in JSON with simple API, competitive pricing, and top notch support. We support all TLDs including new gTLDs as well as IP addresses. Spend no more than necessary to get WHOIS data for your business.
Get complete reports of domains, emails, or IP addresses with connections & leads in an in-depth, plain language document explaining the findings as developed by highly seasoned online investigators — for less than you'd expect.