Understand app-ads.txt

Last year, the ad tech industry struck back at one of its most elusive problems: widespread domain spoofing that let unauthorized developers sell premium inventory they didn’t actually have. As a defense, over two million developers adopted ads.txt, a simple-text public record of Authorized Digital Sellers for a particular publisher’s inventory, to make sure they didn’t lose money from DSPs and programmatic buyers who avoid noncompliant publishers. Thanks to buyers’ ability to crawl ads.txt and verify seller authenticity, this has quickly become a standard for protecting brands.

The time has come for ads.text to evolve in-app. The introduction of app-ads.txt is an important method for mobile app devs to similarly eliminate fraud and improve transparency.

Like ads.txt, app-ads.txt is a text file that app developers upload to their publisher website. It lists all ad sources authorized to sell that publisher’s inventory. The IAB created a system that allows buyers to distinguish the authorized sellers for specific in-app inventory, weeding out the undesirables.

A DSP wanting to bid on an app’s inventory crawls the app-ads.txt file on a developer’s website to verify which ad sources are authorized to sell that app’s inventory. The DSP will only accept bid requests from ad sources listed on the file and authorized by the app developer.

Capture More Revenue With app-ads.txt

  • Authorized in-app inventory: An ever-increasing number of brands is looking to advertise in-app today. Brand buyers now rely on an adherence to app-ads.txt to make sure they don’t buy unauthorized inventory from app developers and negatively impact campaign performance. Developers who don’t implement app-ads.txt can be removed from any brand buyer’s target media list. That’s why joining the app-ads.txt movement is crucial for publishers to maintain their revenue.
  • Ad fraud prevention: app-ads.txt blocks unauthorized developers who impersonate legitimate apps and mislead DSPs into spending brand budgets on fake inventory. With fraud instances minimized, authentic developers can retain more of the ad revenue from inventory genuinely targeted to their app.

Create an app-ads.txt File

Step 1. List Your Developer Website URL in Your App Store

You must list your Developer Website URL in the GooglePlay and iTunes app stores. There must be a valid developer website URL in all app stores hosting your apps.

Step 2. Provide the Publisher Website URL in Your App Store Listing

Make sure that your publisher website URL (not the app-specific URL)  is added in your app store listings, particularly the 'developer website' or 'app support' links on your App and Play Store pages. Advertising platforms will use this URL to verify the app-ads.txt file by visiting your host domain and then appending app-ads.txt to reach the subdomain where your app-ads.txt should live; e.g., There should be a consistent host domain across all your app store fronts. Also, double-check that your ad network (e.g., Liftoff) account in the Liftoff Monetize Dashboard has the correct app store URLs entered for your apps.

Step 3. Reach Out to All Ad Sources (Direct, Resellers, etc.)

Get in touch with your direct ad sources and ask for their app-ads.txt line, following the IAB’s structure below:

Ad source domain, your publisher account ID, type of relationship (direct or reseller), TAG cert ID

Example:, 1234, DIRECT, 5678

If your partners are using third-party resellers to sell your inventory, they should be listed as “reseller.”

Example:, 1234, RESELLER, 6789

Do not add any provider to your app-ads.txt file unless you or your partner have a direct relationship with them.

We have made it easier for you to include Liftoff's list of entries so that you don’t have to construct it independently. Download the file, copy and paste the text block (only the entries table), and include it in your txt file, along with entries you may have from your other monetization partners. Remember to replace [yourLiftoffMonetizePublisherAccountID] with your Liftoff Monetize Account ID, which can be found in your Liftoff Monetize dashboard.

Download this file  Liftoff Monetize app-ads.txt file

Step 4. Write the app-ads.txt File

Create and save an app-ads.txt file in any text editor (e.g., Notepad), listing out all the lines you received from your ad source partners.

Step 5. Upload the app-ads.txt File

Upload the app-ads.txt file to the root of your website domain (e.g.,


Need further assistance, feel free to reach out to us, we’re here to help!

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