Subdomains Lookup | Find all subdomains | WhoisXML API

Find all the subdomains of a domain with Subdomains Lookup tools

Our subdomain finder tools allow you to discover the subdomains of any target domain to uncover potential attack entry points. Find systems that are less protected and thus more vulnerable to attacks.

500 free API requests. No credit card required.

2.3 Billion+Subdomains
1 Million+Subdomains discovered daily
52,000+Satisfied customers
14+Years of data crawling

Our subdomain finder product line includes:


Just take a domain name and instantly get a complete list of subdomains with relevant update dates.

Subdomains Lookup | WhoisXML API
Subdomains Lookup API | WhoisXML API


With one API call, get a list of all subdomains related to a given domain name to discover any company’s web infrastructure, including yours so you can reduce your potential attack surface.

Subdomains Data Feed

We provide a large subdomain repository with 2.3+ billion records updated weekly and available for download in the form of an exhaustive and well-parsed comma-separated values (CSV) file.

Subdomains Data Feed | WhoisXML API

Benefits of Subdomains Lookup

  • Based on up-to-date data

    Each subdomain search gives you a list of all the subdomains of a domain from a large database gathered in over a decade of data crawling and growing by over 1 million subdomains daily on average.

  • Quick results

    Just take a domain name and do an instant subdomain enumeration for any target domain.

  • Handy

    Don’t bother with manual subdomain research with the help of our handy and fast Subdomains Lookup API.

What is Subdomain Lookup?

A subdomain lookup tool, also known as a subdomain finder tool, helps identify subdomains associated with a domain name using passive DNS data. It can have different use cases like supporting cybersecurity research, spotting dangling records, and creating lists of possibly suspicious subdomain artifacts.

subdomain lookup

Do you know just how much big brands are affected by wild subdomain footprints?

Check our white paper “The Secret Life of Wild Subdomains” for an overview of the subdomain surface of 10 of today’s most spoofed brands.

Download white paper
Subdomains Lookup Overview | WhoisXML API

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