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.

surfcheck.info achieves the best ad optimization: its app-ads.txt has no errors and matches what its 3 ad networks expect (100% of 3 lines).

Checked 20 Oct 2026. 92 lines, 81 unique records, 10 duplicates, 0 invalid lines, 5 ad networks detected.

Amazon Publisher Services — account 34707388-10ee-4cca-8eb7-79dec077f907: 1 line in the file
Xandr (Microsoft) — account 11405: 1 line in the file
Index Exchange — account 191151: 1 line in the file
Mintegral — partner (reseller) lines only: 13 lines in the file, 400 expected lines missing
Yango Ads — partner (reseller) lines only: 15 lines in the file, 400 expected lines missing

Yes — https://surfcheck.info/app-ads.txt has 92 lines (checked 20 Oct 2026).

Its app-ads.txt lists Amazon Publisher Services, Xandr (Microsoft), Index Exchange, Mintegral, Yango Ads.

surfcheck.info achieves the best ad optimization: its app-ads.txt has no errors and matches what its 3 ad networks expect (100% of 3 lines).