An IAB Tech Lab standard that lets app publishers declare which ad networks are authorized to sell their inventory.

Where do I put the app-ads.txt file?

At the root of the developer website listed in your App Store / Google Play page, e.g. https://studio.com/app-ads.txt.

What is a Certification Authority ID?

An optional TAG-ID of the ad system, the 4th field of an app-ads.txt record.

play2daygames.com achieves the best ad optimization: its app-ads.txt has no errors and matches what its 2 ad networks expect (100% of 2 lines).

Checked 19 Oct 2026. 3 lines, 3 unique records, 0 duplicates, 0 invalid lines, 2 ad networks detected.

Meta Audience Network — accounts 494733034989017, 1512805083258072: 2 lines in the file
Google AdMob — account pub-3555124779011239: 1 line in the file

Yes — https://play2daygames.com/app-ads.txt has 3 lines (checked 19 Oct 2026).

Its app-ads.txt lists Meta Audience Network, Google AdMob.

play2daygames.com achieves the best ad optimization: its app-ads.txt has no errors and matches what its 2 ad networks expect (100% of 2 lines).