Whereas Ads.txt has grown widely adopted over the past few years, App-Ads.txt hasn’t become mainstream yet. However, the recent surge in its implementation suggests it’s time to get a grip.

Back in 2017 when IAB introduced the Ads.txt Initiative, market forecasts on its industry-wide adoption weren’t too optimistic at first. However, looking back from 2020, it has definitely become somewhat a game changer producing a huge shift towards higher transparency across the digital advertising landscape.

According to the IAB Europe report, the share of publishers who have implemented /ads.txt has already exceeded 56%, and the increase continues.

As for App-Ads.txt, the numbers are also encouraging, but let’s take a step back.

What is App-Ads.txt?

In brief, the App-Ads.txt refers to Authorized Sellers for Apps, which is an extension of the Ads.txt standard, specifically developed to fight ad fraud in the mobile app and CTV advertising segments.

Similarly to the original Ads.txt, the App-Ads.txt specification implies an app publisher provides a list of authorized sellers of its ad inventory and makes it available for referencing in the root folder of their website domain, in the /app-ads.txt file.

Why App Publishers Need App-Ads.txt

Implementing /app-ads.txt is not mandatory, and most app publishers initially took a so-to-speak “wait and see” approach after the release of its first version back in March 2019.

However, after the major DSPs and ad exchanges started to enforce App-Ads.txt in Q3 2019, the numbers skyrocketed. According to the recent Pixalate report, 182 000+ apps already have /app-ads.txt, and this number is continuously growing. 

Quite predictably, the adoption of /app-ads.txt or the lack of it, will have an increasingly bigger impact on the app publisher’s reputation, hence their advertising revenue, in the near future.

How to Implement App-Ads.txt?

The implementation flow for App-Ads.txt is similar to the Ads.txt, with a few minor differences:

1. Prior to publishing an /app-ads.txt file, review and ensure you provide a relevant website URL on your app page in the store listing.

2. Gather all information about the authorized sellers of your app ad inventory, and save data about each ad partner to the text file (e.g. using Notepad) under the name “app-ads.txt”, in the following format:

<FIELD 1>, <FIELD 2>, <FIELD 3>, <FIELD 4>, where
  • FIELD 1 should include the Domain name;
  • FIELD 2 – the Publisher’s account ID;
  • FIELD 3 –  the Account type (i.e. DIRECT or RESELLER), and 
  • FIELD 4 (Optional) – the Certification Authority ID.

3. Publish the file to the root folder of your website properties (the path to file should look like: example.com/app-ads.txt*).

*Note! Make sure to truncate your website URL to just the domain name (without the www. or m. prefixes), then append “/app-ads.txt”.

Read the IAB Tech Lab specification guide for more implementation details.