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.

omroepbrabant.nl achieves the best ad optimization: its app-ads.txt has no errors and matches what its 6 ad networks expect (100% of 7 lines).

Checked 20 Oct 2026. 91 lines, 81 unique records, 3 duplicates, 0 invalid lines, 10 ad networks detected.

OpenX — account 540717793: 1 line in the file
Magnite (Rubicon) — account 18910: 1 line in the file
Google AdMob — accounts pub-3568104463520687, pub-3959445697581997: 2 lines in the file
PubMatic — account 158547: 1 line in the file
Index Exchange — account 190848: 1 line in the file
TripleLift — accounts 9113, 9113-EB: 2 lines in the file
Mintegral — partner (reseller) lines only: 25 lines in the file, 400 expected lines missing
Yango Ads — partner (reseller) lines only: 26 lines in the file, 400 expected lines missing
DSP Exchange — 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://omroepbrabant.nl/app-ads.txt has 91 lines (checked 20 Oct 2026).

Its app-ads.txt lists OpenX, Magnite (Rubicon), Google AdMob, PubMatic, Index Exchange, TripleLift, Mintegral, Yango Ads, DSP Exchange, Bidmachine.

omroepbrabant.nl achieves the best ad optimization: its app-ads.txt has no errors and matches what its 6 ad networks expect (100% of 7 lines).