Understand app-ads.txt

Publishers use the app-ads.txt file to designate authorized digital sellers of their ad inventory, and DSPs use it to validate that they are buying inventory through an authorized source. Implementation is optional, but we strongly recommend it for the purpose of transparency.

In 2018, the IAB launched ads.txt, a file enabling web publishers to designate authorized digital sellers of their ad inventory. app-ads.txt is the mobile in-app equivalent of this specification, which mobile publishers can implement. This text file declares your Authorized Digital Seller (ADS) List to prevent unauthorized sellers from profiting off your inventory or from selling counterfeit inventory.

Implement app-ads.txt

To implement app-ads.txt you’ll need to do the following;

  1. Provide a developer website in your app store listings. Ensure that the proper developer website URL is accessible in the developer website section of the app store.
  2. Publish an app-ads.txt file. Create this document in Notepad, and include the following data:
    • Ad Source Domain: For NinthDecimal, this value is
    • Publisher ID: Refer to your endpoint to find your Publisher ID.
    • Type of Relationship: All of NinthDecimal’s publisher relationships are direct, so the value for NinthDecimal is always designated as direct.
    • Ad Source ID: This is the ad source’s TAG ID. For NinthDecimal, the value is 3aff2148687b274b.
    • Publish the app-ads.txt file in the root of the app developer’s developer website; for example,

Here is an example NinthDecimal’s entry in a publisher’s app-ads.txt file. The four parameters are separated by commas, with a separate line for each authorized partner:

NinthDecimal’s app-ads.txt

Last Updated on February 01, 2020
Use this to add NinthDecimal’s app-ads.txt lines.

Direct Seller Line, [pub id]. DIRECT, 3aff2148687b274b

Reseller Lines

BUYER AD FORMAT, 16676, RESELLER, 0bfd66d529a55807 All, 156372, RESELLER, 5d62403b186f2ace All, 540311484, RESELLER, 6a698e2ec38604c6 All