If you are replacing WhoisXML API because you need more features (not less), DomainTools is the upgrade. It is the most expensive option but the most authoritative for law enforcement and Fortune 500 SOCs.

C99 is an "all-in-one" API that includes WHOIS alongside dozens of other tools (subdomain scanners, reverse IP, port scans). It is a favorite among indie hackers and red-teamers.

In addition to their Whois Lookup API, DomainTools also offers a more comprehensive DomainTools API. This API provides access to a wide range of domain data, including domain registration records, DNS records, and more.

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