How to implement ads.txt

Who it may concern?

As of the ads.txt Version 1.0.1 released in September, 2017, the following list of actors can get on board with ads.txt:

  1. A domain owner that sells ads on SSPs/Ad Exchanges, using own account.
  2. A network or sales house that sells programmatic ads on behalf of domain owners.
  3. A content syndication partnership in which multiple authorized sellers represent the same inventory.

For convenience, we will refer to any of these entities as ‘publisher’. Publishers have to identify who is authorized to sell their inventory by creating a simple text (.txt) file and placing them at root level of their domains (for example,

As defined in the IAB ads.txt Specification, ‘root domain’ is a one level down from the public suffix list.

How to create an ads.txt file with the ads.txt Generator?


  • Step 1. Fill in your domain name.
  • Step 2. Press the ‘Generate ads.txt’ button afterwards you will receive your ‘/ads.txt’ file, which will be a full list of ‘direct’ advertising systems and ‘resellers’ based on up to ten of your web site pages.
  • Step 3. Check Advertising systems, enter their IDs and other additional information.
  • Step 4. Enter a valid email address in order to receive your ‘/ads.txt’ file


What will my ‘/ads.txt’ file contain?


  • Advertising System Domain Name (Required). This is an operational domain of an SSP, Ad Exchange, Header Wrapper or other system that ad bidders connect to, in other words this is a domain that is a part of an ad serving URL;
  • Publisher Account ID (Required). This is the identifier associated with the seller or reseller account within the advertising system (Advertising System Domain). In OpenRTB protocol and OpenDirect API this is a publisher ID.
  • Type of Account/Relationship (Required). This term describes publisher relationship with advertising system:
    • DIRECT. This is a type of direct business contract between a Publisher and an advertising system (e.g. when domain owners sell on Exchanges/SSPs through their own accounts);
    • RESELLER. This is a type of business contract that indicates that a Publisher has authorized another entity to be in charge of selling/reselling of their ad space (e.g. networks and sales houses who sell impressions programmatically on behalf of domain owners).
  • Certification Authority ID (Optional). This term stands for the TAG ID (Trustworthy Accountability Group), an ID that uniquely identifies the advertising system within a certification authority (this ID maps to Advertising System Domain).


There are several variable fields indicated with # symbol officially supported by ads.txt, but considered as comments and, subsequently ignored by buyers’ Ads.txt Crawlers:

  • Contact information (Optional)
  • Subdomain (Optional)