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.

virginmedia.com achieves the best ad optimization: its app-ads.txt has no errors and matches what its 4 ad networks expect (100% of 6 lines).

Checked 20 Oct 2026. 174 lines, 167 unique records, 2 duplicates, 0 invalid lines, 10 ad networks detected.

Index Exchange — accounts 214644, 208759: 2 lines in the file
Google AdMob — account pub-6341300221321950: 1 line in the file
OpenX — accounts 559783049, 560541172: 2 lines in the file
PubMatic — account 164533: 1 line in the file
Mintegral — partner (reseller) lines only: 10 lines in the file, 400 expected lines missing
BIGO Ads — partner (reseller) lines only: 11 lines in the file, 400 expected lines missing
Yango Ads — partner (reseller) lines only: 12 lines in the file, 400 expected lines missing
DSP Exchange — partner (reseller) lines only: 10 lines in the file, 400 expected lines missing
Verve (PubNative) — partner (reseller) lines only: 12 lines in the file, 400 expected lines missing
Bidmachine — partner (reseller) lines only: 12 lines in the file, 400 expected lines missing

Yes — https://virginmedia.com/app-ads.txt has 174 lines (checked 20 Oct 2026).

Its app-ads.txt lists Index Exchange, Google AdMob, OpenX, PubMatic, Mintegral, BIGO Ads, Yango Ads, DSP Exchange, Verve (PubNative), Bidmachine.

virginmedia.com achieves the best ad optimization: its app-ads.txt has no errors and matches what its 4 ad networks expect (100% of 6 lines).