Whoisology - Connected database of whois records and whois history
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.
WhoisAPI - WhoisAPI is the premier provider of freshly parsed whois data for domain names and IP addresses...
WebCargo - Optimize your workflow by offloading it to us. Useful API's with seamless integration that scale to your needs.
ICANN WHOIS - The official ICANN WHOIS search for domain lookups.
JSON WHOIS API - Parsed domain WHOIS data from any WHOIS server via RESTful API with metered pay as you pricing.