Run Only “Valid” Ads.txt Lines To Prevent Revenue Loss

This post was most recently updated on August 17th, 2022

The Authorized Digital Sellers initiative which is most commonly known as ads.txt, was established in order to prevent counterfeit inventory in the digital advertising ecosystem. It allows publishers to declare which entities or exchanges are authorized to sell their traffic.


In order for ads.txt to work as expected, you need to ensure that you have the correct format. Each line should contain between 3 to 4 fields of information. The first three fields are required, and the fourth one is optional.

<FIELD #1>, <FIELD #2>, <FIELD #3>, <FIELD #4>

Here’s an excerpt from the IAB Tech Lab ads.txt specification document that explains what each field means and its purpose:

ads txt 1


Example ads.txt line:, 57013, RESELLER, abc123

Common mistakes in ads.txt

#1 – Incorrectly formatted account ID or publisher ID (field #2)

This is possibly a typo. Reach out to your ad network representative for them to re-check and send the correct format.

#2 – Invalid exchange domain

If the exchange domain is not recognized, it doesn’t necessarily mean it’s invalid. It sometimes means it’s not yet recognized widely but still pays to re-check with your provider.

#3 – Missing any of the first three required fields

The first three fields are non-negotiable. Make sure all three are complete in every line.

#4 – Incorrect relationship value

The only acceptable value is either RESELLER or DIRECT. Nothing else.

#5 – Invalid lines that are not meant as ads.txt records

Lines that are obviously not for the purpose of ads.txt.

#6 – Unusual characters or symbols

Check if this was a typo and reach out to your provider to confirm.


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