Reverse IP API to get all domains sharing an IP | WhoisXML API

Reverse IP API reveals all domains that share an IP address in a single API call

Get a list of all domains associated with an IP address via API calls with outputs in JSON and XML formats.

Get started

500 free API credits. No credit card required.

50 Billion+Domains and subdomains
Billions"A" records
Millions"A" records added weekly
52,000+Satisfied customers


  • Сomprehensive

    Determine infrastructure connections between hostnames and IP addresses using one of the biggest archives of Domain Name System (DNS) records today.

  • Fast

    Reverse IP & DNS API lets you query up to 10 IPs per second so you can quickly identify which domains are connected.

  • Handy

    Our Reverse IP & DNS API comes with code samples for easy integration in several programming languages. It’s also available as a Splunk Enterprise application.

What is a reverse IP API?

A reverse IP API is an intelligence consumption model with data delivery via API calls. The API establishes which domains might be using the same IP to host their websites’ contents. It allows website owners to check if their IP address is shared or dedicated and serves several purposes.

Practical usage

Cybersecurity research

Cybersecurity research

Identify all potentially dangerous domains that share the same IP with known malicious websites.

Penetration testing

Identify your attack surface by discovering all the hosts and IPs related to a given target website/IP address. You can also check if you have the same IP addresses as vulnerable websites with Reverse IP API. Further analysis is possible, too, with Reverse WHOIS API and Reverse WHOIS Search.

Incident response and threat intelligence

During or after an intrusion or incident, you can use Reverse IP capabilities to identify the attackers’ hostnames.

SEO and digital marketing

You can also use Reverse IP API to ensure that your website’s IP address is not being used by any other domain. That may lower your search engine ranking and move your site to a less reputable area of the Internet.

SEO and digital marketing
Web hosting reputation and oversubscription management

Web hosting reputation and oversubscription management

Hosting your website on a crowded IP address or one with a bad reputation due to malicious neighboring domains can negatively affect your website performance and how you are perceived on the web. It may even land you on a blacklist.

Domain asset management & brand protection

Our Reverse IP API enables you to conduct an inventory of all your websites or those of your competitors hosted on the same IP address. The API also helps with brand protection, as it can find other domains that potential attackers own and pinpoint otherwise-unknown related web properties that can cause harm.

Domain asset management & brand protection
DNS Database Download

Get access to the biggest Passive DNS Database

DNS Database Download is a large historical DNS record repository with several billions of historical DNS events as specified in our files covering A, MX, NS, TXT, CNAME, and SOA records.

Request a Quote

Domain Name System Primer

In this white paper, we give an overview of the Domain Name System, or DNS, one of the pillars of the Internet.

Read more
Reverse IP/DNS API | WhoisXML API

Get 500 free API credits. No credit card required.

Get started

Premium API Services

Our APIs are available in an enhanced version that offers better performance with a dedicated load balancer and a premium endpoint to enable faster throttling for large-scale API deployments.

Learn more

Enterprise API Packages

Reverse IP/DNS capabilities are only a part of our extensive set of APIs. Get complete access to domain, IP, and DNS intelligence with an annual WhoisXML API subscription.

Learn more