The app-ads.txt file consists of a list of authorized digital sellers. This file was created by IAB, to combat fraud and to create transparency in the advertising ecosystem. The file verifies the legitimacy of sellers, protecting against fraud and misrepresented domains.
Developers must host this file in the root of the developer website. Brand advertisers and demand-side platforms (DSPs) scrape this file and cross-reference it when they buy ad inventory programmatically via exchanges, supply-side platforms (SSPs), and ad networks.
While implementing app-ads.txt is not mandatory in most cases, failing to do so will cause developers to lose significant ad revenue for the following reasons:
DSPs use this file to understand the supply chain of inventory they are buying.
Some DSPs will only buy from developers that have correctly implemented this file.
Developers that properly declare their authorized sellers help advertisers greatly reduce the risk of counterfeit inventory, which over time funnels more advertising dollars to quality developers.
Setting up app-ads.txt for the first time
To set up app-ads.txt from the Monetization dashboard:
Select Setup > Organization Settings from the secondary navigation menu.
Locate the Developer Website field in the Organization info and click the edit icon.
Enter the URL of the website where your game is listed on the app store. This is usually simple, for example, "https://www.unity3d.com". This field should contain only the root of the developer’s website. For example, you can find this website on the Developer page of Google Play, and in settings on the Apple store.
Scroll to the App-ads.txt section. The App-Ads URL field should be automatically populated. If it is not, see this document about website roots for details.
You'll see a list of authorized digital sellers, presented in the format that the file requires. Using a text editor, create an
app-ads.txtand paste the list from the dashboard into the file.
app-ads.txtfile into the root of the developer website so that it's findable in the location listed in the app-ads URL field.
If everything worked correctly, you'll see a message informing you that no action is needed at this time.
It's important to visit the app-ads.txt setting regularly to see if anything has changed, or to respond to error messages or notifications that you receive.
Here are some issues that can happen, and how to fix them.
Missing or incorrect website
Unity could not find your
app-ads.txt file at the given App-Ads URL.
Solution: Review your Developer Website field in the Organization Info section to make sure it is accurate. Ensure that the correct root is listed as well.
Missing some app-ads.txt entries
You are missing some app-ads.txt entries.
Solution: Navigate to the App-ads.txt section in your Organization settings to refresh the list, then copy-paste the entire updated list into your file.
Frequently asked questions
Is this new? How does it differ from ads.txt?
app-ads.txt is specifically for mobile apps. It provides the same functionality as ads.txt, but resides on the developer's website.
What problem is this intended to solve?
app-ads.txt protects advertisers from buying invalid or fraudulent traffic, and protects publishers from losing revenue to malicious sources intercepting their demand.
Why should publishers adopt app-ads.txt?
Moving forward, a number of major Brand advertisers and DSPs will only buy inventory from authorized inventories, creating a strong incentive for publishers to adopt app-ads.txt. To stay ahead of this shift in the industry and avoid missing out on revenue, Unity recommends implementing this as early as possible.
What is Unity’s position on app-ads.txt?
Unity strongly supports this initiative because it combats fraud and creates more transparency for mobile advertising. App developers who implement this will, in turn, see more premium advertisers and incremental revenue.
Why should advertisers adopt app-ads.txt?
As with ads.txt for web, this file gives advertisers greater assurance that they are buying legitimate impressions from authorized resellers.