Tips for Publishers: How to implement App-ads.txt quickly to avoid revenue loss

Because major DSPs like The Trade Desk and Google DV360 as well as SSPs like Rubicon Project are starting stricter enforcement of app-ads.txt.

Tips for Publishers: How to implement App-ads.txt quickly to avoid revenue loss

1 - App-ads.txt? What’s that again?

Quick refresher: In its continued effort to improve quality in the ad tech ecosystem, the IAB introduced the app-ads.txt earlier this year. An extension of ads.txt, the standard aims to curb the spoofing of applications distributed through channels such as mobile app stores and connected television app stores. Smart is a strong supporter of this quality initiative, which is gaining traction.

2 - How does it app-ads.txt actually work?

To participate in the authorized seller scheme, the developer’s website URL must be published in the listing metadata of all app stores distributing the application. By crawling the app listing pages in the app stores, buyers and advertisers will be led to the app-ads.txt file, the contents of which will allow them to confirm authorized resellers and target authentic inventory. 

Get the complete app-ads.txt technical documentation here

3 - As an app developer, why should I care about app-ads.txt?

It took about 6 months, but now the buy side is getting serious about app-ads.txt. 

  • On August 27, Google’s Display & Video 360 announced they will begin scanning app-ads.txt files and subsequently blocking the sale of any unauthorized inventory 
  • On September 20, The Trade Desk began offering buyers a filter to prevent bids on non-ads.txt verified inventory
  • Effective October 15th, Adform DSP will start to actively filter unauthorized sellers when an app-ads.txt file is published by the publisher.
  • At the end of September, Rubicon started monetizing only inventory that has an app-adst.txt file containing Rubicon line (Smart is connected to Rubicon for server-to-server, so this concerns our Publishers, too.)

And if we take ads.txt as an example, it’s becoming clear that brands are buying where they feel safe. Taboola found that among 4,000 publishers, those with an ads.txt file displayed an 8% uplift in the U.S. and an 11% uplift in EMEA. Similarly, Pubgalaxy found publishers with and ads.txt file increased their RPM by over 8%.

The bottom line: We’re urging our app publishers to implement app-ads.txt immediately to avoid losing a large part of their revenue.

4 - Tips for implementing your file


  1. First, make sure you’ve properly listed your “developer URL” on the app store listings where your app can be downloaded. This URL is where crawlers will search for your app-ads.txt file. 

For the Google Play Store it’s easy, just fill in the URL in the “Website” field


For the App Store, we recommend you update the “Marketing URL” as well as the “Support URL”. Why? The IAB specs were based on the Google Play Store, so they are unspecific about where developers should place the URL in the Apple App Store. The result is that some crawlers are searching for the URL in the “Website URL” field, while others are searching for it in the “Support URL” field. Play it safe, ensure both fields are filled in, and that your app-ads.txt file is placed on the two URLs.


2. Be sure to add or update your URLs right away. The “support URL” might take a few days to be processed by the App Store. 

3. Implement an app-ads.txt file of authorized sellers on the app developer’s website and be sure to list Smart as an authorized partner.

a.  ⚠️ Make sure your file is correct and free of syntax errors! Mistakes will result in revenue losses. (More tips here from the IAB.)

b. Make sure to add the server-to-server connections, too! That way you’ll have access to all our demand sources! (We know some publishers like to limit the amount of players listed in their app-ads.txt lines. So, check out why you should add each one here.)

4. Ensure store listing URLs, app bundles/store IDs are properly furnished to Smart. Learn how to do it here.



  1. Inform the developers of the apps you are monetizing to implement an app-ads.txt file in the roots of their developer’s websites. The Smart ID and your seller account ID have to be listed.
  2. Then, the app developers have to fill in the website URL on the app store listings

where the apps can be downloaded.

  1. Provide the store listing URL (as well as app bundle / store id) on bid requests.

For more information about App-ads.txt do not hesitate to consult our support page

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