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.

2gb.com is missing out on higher CPMs: its app-ads.txt has 2 invalid lines. Buyers' crawlers skip invalid lines, so those sellers can't be verified.

Checked 19 Oct 2026. 65 lines, 52 unique records, 1 duplicates, 2 invalid lines, 5 ad networks detected.

Google AdMob — accounts pub-4865685300463942, pub-5329632245583336, pub-5285018697230818: 3 lines in the file
Magnite (Rubicon) — accounts 18022, 18250: 2 lines in the file
Index Exchange — account 189843: 1 line in the file
Mintegral — partner (reseller) lines only: 12 lines in the file, 400 expected lines missing
Yango Ads — partner (reseller) lines only: 12 lines in the file, 400 expected lines missing

Yes — https://2gb.com/app-ads.txt has 65 lines (checked 19 Oct 2026).

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

2gb.com is missing out on higher CPMs: its app-ads.txt has 2 invalid lines. Buyers' crawlers skip invalid lines, so those sellers can't be verified.