App-ads.txt helps ensure that applications with in-app ads belong to publishers. It is designed to protect publishers and developers from fraud.
Publishers are required to create an app-ads.txt for applications and upload it to the root directory of the application website listed on Google Play or the App Store. App-ads.txt file like below is provided as a code snippet on Google AdMob.
google.com, , DIRECT, 0000000000000000
This snippet does not contain the publisher ID. You, the publisher, manually add your publisher ID, which can be found in the profile section in the upper right-hand corner, to the second field.
Unless your app-ads.txt is properly formatted, AdMob crawl status is set to “No app-ads.txt file found“. If your app-ads.txt could be accessed via AdMob app-ads.txt link and AdMob still did not find your app-ads.txt file, your file is very likely to be malformed or the character encoding of the file is invalid.
