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.

campercontact.com achieves the best ad optimization: its app-ads.txt has no errors and matches what its 5 ad networks expect (100% of 8 lines).

Checked 20 Oct 2026. 14 lines, 14 unique records, 0 duplicates, 0 invalid lines, 5 ad networks detected.

Google AdMob — accounts pub-7939627363540437, pub-6882178214885631: 2 lines in the file
PubMatic — accounts 158160, 158130: 2 lines in the file
Index Exchange — account 191000: 1 line in the file
Xandr (Microsoft) — accounts 12382, 6924: 2 lines in the file
Magnite (Rubicon) — accounts 26188, 26190: 2 lines in the file

Yes — https://campercontact.com/app-ads.txt has 14 lines (checked 20 Oct 2026).

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

campercontact.com achieves the best ad optimization: its app-ads.txt has no errors and matches what its 5 ad networks expect (100% of 8 lines).