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If you are a mobile app developer, the IAB’s App-ads.txt project enables you to declare who is authorized to sell your inventory. By creating your own app-ads.txt file, you can protect your inventory from app spoofing and unauthorized sellers.

While not mandatory, using app-ads.txt is highly recommended because it gives demand-side platforms (DSPs) a simple way to check if inventory from a particular source has been authorized for sale by you.

You can learn more by reading the IAB Partner Interaction Guide.

To take advantage of app-ads.txt, see the following table for the information that goes into the file. Then, follow the steps for creating and posting the file.

App-ads.txt Fields

If you have not received the OpenX-specific line(s) for your ads.txt file, contact OpenX. For your reference, each OpenX-specific line in the ads.txt file should include:

FieldIAB Field NameDescription & ExampleRequired?
Field 1Domain Name of the Advertising SystemThe domain name of the system to which bidders connect.

Field 2Seller Account IDThe publisher account ID in OpenX.

Note: OpenX provides you with OpenX-specific line(s) for your ads.txt file. If you have not received them, contact OpenX.

Example: 123456789
Field 3TYPE OF ACCOUNT/RELATIONSHIPThe type of account, for example either:

DIRECT: The publisher directly controls the account in Field 2 on the system in Field 1.
RESELLER: The publisher has authorized another entity to control the account indicated in Field 2 and resell their ad space via the system in Field 1.

Note: The IAB specifies that DSPs should treat this field as case insensitive when interpreting data. For simplicity and uniformity, OpenX recommends that the value in this field be typed in all capital letters.
Field 4Certification Authority IDAn ID that uniquely identifies the system in Field 1 within a certification authority. OpenX has been thoroughly vetted and certified by the Trustworthy Accountability Group (TAG). The TAG ID for all OpenX lines in the ads.txt file is 6a698e2ec38604c6.

Note: While this field is optional, OpenX highly recommends inserting the TAG ID in the OpenX lines of your ads.txt file. This field may become required in the future. Utilizing it now saves you from needing to revise it at a later time.

Example: 6a698e2ec38604c6
Optional, but highly recommended

App-ads.txt Format

Each app-ads.txt line is formatted as follows:

 Domain Name of the Advertising System, OpenX Account ID, TYPE OF ACCOUNT/RELATIONSHIP, (Optional) Certification Authority ID

In this live example, the publisher has two OpenX accounts:

  • The first line of the example illustrates that the publisher is using OpenX directly, with an account ID of 123456789.
  • The second line of the example shows the publisher authorized another entity as a reseller of the ad space. That entity has an account ID of 987654321.

Creating and Posting App-ads.txt

To create and post app-ads.txt:

  1. Contact your OpenX Account Manager to request the lines of text that identify OpenX as an authorized partner.

  2. If you don’t already have one, create a .txt file and name it app-ads.txt.

  3. Copy the text provided by OpenX and paste it into your app-ads.txt file.


    You can find your account Ads.txt in Administration > Accounts > Publisher Account > Details > Ads.txt.

  4. For every other authorized partner, enter a new line with the information described in App-ads.txt fields. Make sure to use the same formatting as for the OpenX-related lines.

    Adding lines for other partners before you post the file helps avoid issues with DSP crawlers. Partners that are missing from your app-ads.txt file may be considered unauthorized sellers by DSPs.

  5. Save the app-ads.txt file.

  6. Post the app-ads.txt file to the root directory of your domain server. This is the domain that is listed in your app store as developer domain.

    The file can be accessible via HTTP or HTTPS but must be located under a standard relative path: app-ads.txt. The HTTP request header must contain Content-Type: text/plain.


Update the app-ads.txt file every time you add a new partner.