Find all domains that use the same name server

Identify domains that share the name server or the same hosting company, using the world’s largest constantly updated database with billions of existing records.

Get started

100 free credits monthly. No credit card required.

1,473,142,430Domains and subdomains
196,463,291NS records updated daily
2,131Satisfied customers


  • Сomprehensive & up-to-date

    We provide service based on world’s largest constantly updated database with 1,473,142,430 domains and subdomains, 196,463,291 NS records updated daily.

  • Fast response & easy integration

    All the results are duly parsed and normalized to a consistent format such as JSON and XML to easily integrate with your business processes.

Practical usage

Increase your website availability

Increase your website availability

Prevent your mail server from being blacklisted. Hosts with dubious reputation may affect email delivery. By using the Reverse MX API service you can identify spamming, phishing and other poor reputation sites on your host.

Security check

  • Uncover connected domains that may otherwise seem unrelated.
  • Perform research on suspicious name servers.
  • Protect your website from defacement.
Security check
DNS Database Download

Get access to the biggest Passive DNS Database

The passive DNS database is a large Historic DNS repository with 2 billion hostnames and hundreds of billions of Historic DNS Lookups. Our comprehensive passive DNS database allows finding out all historical DNS data points for any hostname and ip address.

Download database
Reverse NS API | Whois XML API

Get 100 free credits monthly. No credit card required.

Get started

Trusted by
the smartest

Enterprise API Packages

API access through WhoisXMLAPI can be purchased as an annual subscription. The access pricing is based on the number of queries, which is measured monthly with per-minute rate limits. The pricing structure gives predictability to business planning and solution architecture.

Learn more
Have questions?

We work hard to improve our services for you. As part of that process, we welcome your feedback, questions, and suggestions. Please let us know about your thoughts and feelings, and any way in which you think we can improve our product.

For a quick response, please select the request type that best suits your needs. For more info regarding the request types, see Contact us page.

By submitting, you agree to the Terms of Service and Privacy Policy.

Or shoot us an email to