API Documentation

Registrant Monitor


The DomainTools API is organized into distinct products with queries that follow a RESTful URL structure wherever possible. Each product offers free, un-authenticated access for the sample URLs listed with each product. If you haven’t already, you may want to review the getting started document to learn about authentication and response formats.

The Registrant Monitor API searches the ownership (Whois) records of domain names for specific search terms. The product is ideal for monitoring specific domain owners (such as “DomainTools LLC”) to be alerted whenever their information appears in a newly-registered domain name. The API will also alert you to domains that no longer match a specific term.


NOTE: We are unable to provide a functioning test URL for this product because the data changes each day. See below for a sample response.

By default, the active data set is new or updated Whois records on the day you submit your API query. You should design your system to submit one API query per day for each registrant you want to monitor. If you experience a temporary failure in your processing routines, you can catch up on missing alerts up to six days back by providing the days_back parameter in your request.

Registrant Monitor Parameters

Parameters Description
query Required.
One or more terms separated by the pipe character ( | ).
exclude Whois records with these words will be excluded from the result set.
Separate multiple terms with the pipe character ( | ).
days_back Use this parameter in exceptional circumstances where you need to search
domains registered up to six days prior to the current date. Set the value
to an integer in the range of 1-6.
limit Limit the number of matched domain names that are returned in your result set.

For best results, schedule your daily update to occur no sooner than 3am Pacific time. This ensures the data has been fully processed and is ready for your use.

Because each query consumes resources regardless of whether a match is found, your API account will be charged for each request you submit to the API even if no domain names match your query.

Sample Response

   response: {
     query: "DomainTools",
     limit: 500,
     total: 2,
     date: "2011-03-02",
     alerts: [
         domain: "reversewhois.com",
         match_type: "added"
         current_owner: "DomainTools LLC"
         created: "2011-02-01"
         modified: "2011-03-02"
         last_owner: ""
         domain: "external-systems.com",
         match_type: "removed"
         current_owner: "Domain Administration"
         created: "1999-10-17"
         modified: "2011-03-02"
         last_owner: "DomainTools LLC"

You must provide your
API credentials
to use this API.

General Information