Reverse WHOIS Lookup

Reverse WHOIS Search lets you find all domains associated with a specific registrant attribute — such as an email address, organization name, registrant name, or phone number — rather than looking up a single domain. It answers the question: 'What other domains does this person or company own?'

You can perform a reverse lookup by: registrant email address, registrant name, registrant organization, registrant phone number, registrar name, nameserver hostname, and more. WhoisFreaks indexes all publicly available WHOIS fields.

Standard WHOIS takes a domain and returns its owner data. Reverse WHOIS takes an owner attribute (e.g., an email) and returns all domains linked to it — effectively inverting the relationship.

Yes. Searching by organization name or a company's domain-registration email typically surfaces the full portfolio of domains registered by that entity. This is valuable for competitive intelligence, brand monitoring, and M&A due diligence.

Post-GDPR records frequently redact contact data, which limits reverse searches on newer registrations. However, WhoisFreaks' database retains historical pre-redaction records, so reverse searches often surface domains that were registered before privacy rules took effect, providing meaningful results even for older portfolios.

Key use cases include: identifying all domains controlled by a threat actor (by pivoting on shared registrant data), brand protection (finding unauthorized domains using your company name or trademark), competitive intelligence, fraud investigation (linking domains to scam operators), and due diligence on domain portfolio acquisitions.

The free tool returns a limited result set. Full results — which may number in the thousands for prolific registrants — are available through the Reverse WHOIS API with pagination support.