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.

aljazeera.com achieves the best ad optimization: its app-ads.txt has no errors and matches what its 4 ad networks expect (100% of 4 lines).

Checked 20 Oct 2026. 31 lines, 15 unique records, 0 duplicates, 0 invalid lines, 4 ad networks detected.

Google AdMob — accounts pub-4191821473966699, pub-8621187278397, pub-8622401187278397 and 1 more: 4 lines in the file
Index Exchange — account 185052: 1 line in the file
Magnite (Rubicon) — account 22884: 1 line in the file
PubMatic — account 159856: 1 line in the file

Yes — https://aljazeera.com/app-ads.txt has 31 lines (checked 20 Oct 2026).

Its app-ads.txt lists Google AdMob, Index Exchange, Magnite (Rubicon), PubMatic.

aljazeera.com achieves the best ad optimization: its app-ads.txt has no errors and matches what its 4 ad networks expect (100% of 4 lines).