Products APIs Data Feeds Web Tools Domain Research & Monitoring Enterprise Packages AI Deep Research
WHOIS / WHOIS History
WHOIS / WHOIS History

Provide current and historical ownership information on domains / IPs. Identify all connections between domains, registrants, registrars, and DNS servers.

DNS / DNS History
DNS / DNS History

Look into all current and historical DNS / IP connections between domains and A, MX, NS, and other records. Monitor suspicious changes to DNS records.

IP Geolocation / IP Netblocks
IP Geolocation / IP Netblocks

Get detailed context on an IP address, including its user’s geolocation, time zone, connected domains, connection type, IP range, ASN, and other network ownership details.

Domain Research Suite (DRS)
Domain Research Suite (DRS)

Access our web-based solution to dig into and monitor all domain events of interest.

Domain Research Suite (DRS)
Domain Research Suite (DRS)

Get access to a web-based enterprise-grade solution to search and monitor domain registrations and ownership details for branded terms, fuzzy matches, registrants of interest, and more.

Research
Monitoring
White-Label
Predictive Threat Intelligence Feeds
Predictive Threat Intelligence Feeds

Predictive threat intelligence is your best first line of defense. Subscribe to the feeds to strengthen your cybersecurity posture. Contact us today for more information.

WhoisXML API Internet Infrastructure
Internet Infrastructure

Unlock integrated intelligence on Internet properties and their ownership, infrastructure, and other attributes.

Enterprise API Packages
Enterprise API Packages

Our complete set of domain, IP, and DNS intelligence available via API calls as an annual subscription with predictable pricing.

Security Intelligence (SI) Suite
Security Intelligence (SI) Suite

Offers complete access to WHOIS, IP, DNS, and subdomain data for product enrichment, threat hunting and more.

MCP Server
MCP Server

Talk to our APIs using LLMs. Connect your preferred LLM to WhoisXML API and simply chat about WHOIS, DNS, threat intelligence, and more.

Jake AI
Jake AI

I’m your Domain Intelligence Assistant. I make it easy to explore WHOIS, DNS, and threat data from WhoisXML API — I’m cloud-based, fast, and always ready to help.

Discover what you really pay for when buying commercial Internet intelligence data.

Download now
×
Contact Us
API Lookup Suite Pricing

Reverse WHOIS tools and services help you find domain names connected by a registrant identifier

Reverse domain queries via lookups or API calls are useful to identify all domain records that correspond to search terms like a name, an email address, a phone number, etc.

Get started

500 free API requests. No credit card required.

774 Million+Domains tracked
25.5 Billion+WHOIS records
7,596+TLDs and ccTLDs tracked
52,000+Satisfied customers

Our Reverse WHOIS product line includes:

  • Reverse WHOIS API

    Reverse WHOIS API

    Integrate our Reverse WHOIS API into existing security platforms, workflows, and other tools to find domain names connected by a registrant identifier.

    Explore API
  • Reverse WHOIS Lookup

    Reverse WHOIS Lookup

    Easily retrieve a list of domains linked by a specific WHOIS detail via our GUI.

    Explore Lookup
  • Reverse WHOIS Search

    Reverse WHOIS Search

    Conduct Reverse WHOIS searches and enhance investigations using the smart interface and powerful pivoting tools of our Domain Research Suite (DRS) platform.

    Explore Suite

Benefits

  • Establish all known domain name associations with individuals and organizations. Learn more about domain footprints with the consumption model — lookup or API — of your choice.

  • Narrow down your search results by employing filtering parameters to exclude terms that are not relevant to your query.

  • Go with any WHOIS detail you have on hand to run queries via Reverse WHOIS Lookup and make API calls with Reverse WHOIS API. You can use exact-match terms or fuzzy ones for broader results.

  • Results from our lookup tool and API are gathered from the most comprehensive historical WHOIS database on the market with daily updates. All the data returned is parsed, normalized, and consistently formatted.

Product Usage

  • Brand Protection

    Keep an eye out for domain names registered by known cybersquatters and brand infringers by uncovering all web properties tied to public WHOIS details—either current or historical—on record.

  • Threat Actor Profiling

    Using public WHOIS record details as starting points, learn more about threat actors’ current or historical domain footprints and possibly their cybercrime tactics and Indicators of Compromise (IoCs)’ domain infrastructure setup.

  • Competitor Research

    Use our reverse WHOIS solutions to know about upcoming product launches, mergers and acquisitions (M&As), and strategic digital events related to your competitors. Their most recent domain acquisitions can clue you into their future plans.

  • Third-Party Background Checks

    Find out how trustworthy the company you’re hoping to do business with is. Their domains and accompanying WHOIS records may help you confirm claims regarding location, size of operations, and how long a potential partner has been in business.

  • Attack Surface Inventory

    Gauge how large an organization’s potential attack surface is. The entirety of their domain footprint over time obtained via our reverse WHOIS solutions can uncover forgotten domains that could serve as attack vectors.

Reverse WHOIS Overview | WhoisXML API

Get 500 free API credits. No credit card required.

Get started

Trusted by
the smartest
companies

You may be interested

Email Verification
Email Verification

Ensure the validity and quality of any email address.

Learn more
WHOIS Database Download
WHOIS Database Download

We provide complete and relevant domain WHOIS data which can be customized and easily integrated as per your business needs.

Learn more
Screenshot Service
Screenshot Service

Instantly get a screenshot of any web page.

Learn more
IP Netblocks
IP Netblocks

Find out which IP range the particular IP belongs to.

Learn more
Domains & Subdomains Discovery API
Domains & Subdomains Discovery API

Find domains and subdomains related by specific terms in their hostnames.

Learn more
Reverse NS
Reverse NS

Find all domains that use the same name server.

Learn more
Domain Availability
Domain Availability

The most accurate domain availability checker offered on the market.

Learn more
Reverse MX
Reverse MX

Reveal all the domains that use the same mail server.

Learn more
Threat Intelligence API
Threat Intelligence API

Easily identify malicious resources and retrieve their threat information.

Learn more
SSL Certificates API
SSL Certificates API

Check a domain’s SSL certificate chain via API calls.

Learn more
MAC Address Vendor Database
MAC Address Vendor Database

Get the most comprehensive database of registered MAC address blocks, also referred to as OUIs (Organizationally Unique Identifiers).

Learn more
Typosquatting Data Feed
Typosquatting Data Feed

Easily detect all typosquatting domain names as soon as they are registered each day.

Learn more
IP Geolocation
IP Geolocation

Find out the exact physical location of any IP address, email or domain name.

Learn more
Brand Alert
Brand Alert

Monitor exact matches, variations and common misspellings of your brand name & trademarks.

Learn more
WHOIS Search
WHOIS Search

Get well-parsed and normalized WHOIS information for any domain name, IP address or email.

Learn more
Website Categorization
Website Categorization

Define website category of the given domain.

Learn more
Threat Intelligence Data Feeds
Threat Intelligence Data Feeds

Get the most relevant data to be ahead of emerging security threats.

Learn more
MAC Address API
MAC Address API

Get vendor information, detect virtual machines, manufacturer, location, read the information encoded in the MAC address.

Learn more
Domain Reputation API
Domain Reputation API

Assess the domain's or IP addresses reputation and risk profile with a simple score based on a comprehensive...

Learn more
Newly Created Websites Data Feed
Newly Created Websites Data Feed

Get insights for the new business registered on the web.

Learn more
DNS Lookup Services
DNS Lookup Services

Identify who is hosting a particular domain name or website.

Learn more
Domain Registration Streaming
Domain Registration Streaming

Get data feeds of new registered domains along with their WHOIS data generated in real time.

Learn more
Reverse DNS
Reverse DNS

Give the list of domain names tied to the specified DNS records via API calls with outputs in JSON and XML.

Learn more
Subdomains Lookup
Subdomains Lookup

Discover subdomains related to the target domain name.

Learn more
Reverse WHOIS
Reverse WHOIS

Find connections between various domains, individuals and organizations.

Learn more
Newly Registered Domains
Newly Registered Domains

Keep track of the best business opportunities online.

Learn more
Real-time SSL Certificates Streaming
Real-time SSL Certificates Streaming

Get data feeds of SSL certificates along with their well parsed fields in real time. Accurate. Up-to-date.

Learn more
Registrant Alert
Registrant Alert

Find out which domains were added or dropped by registrants, with given search criteria.

Learn more
SSL Certificates Database
SSL Certificates Database

Get the most comprehensive database of SSL (Secure Sockets Layer) Certificates.

Learn more
Domain Research Suite
Domain Research Suite

Enhance your domain research toolkit by our enterprise-grade web-based solution that helps you in searching...

Learn more
Reverse IP
Reverse IP

Find relations like ownership between hostnames and IPs.

Learn more