Whoisology - Connected database of whois records and whois history
HackerOne - HackerOne provides a platform designed to streamline vulnerability coordination and bug bounty program by enlisting hackers.
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.
Acunetix - Audit your website security and web applications for SQL injection, Cross site scripting and other...
WhoisAPI - WhoisAPI is the premier provider of freshly parsed whois data for domain names and IP addresses...
Forcepoint Web Security Suite - Internet Security