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.

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

Checked 20 Oct 2026. 56 lines, 45 unique records, 0 duplicates, 0 invalid lines, 7 ad networks detected.

Google AdMob — accounts pub-5772585630217132, pub-0627101520158699: 2 lines in the file
OpenX — account 540717738: 1 line in the file
Sovrn — account 272455-eb: 1 line in the file
Yahoo — account 58722: 1 line in the file
Magnite (Rubicon) — account 20102: 1 line in the file
PubMatic — account 159744: 1 line in the file
DSP Exchange — partner (reseller) lines only: 14 lines in the file, 400 expected lines missing

Yes — https://viamichelin.com/app-ads.txt has 56 lines (checked 20 Oct 2026).

Its app-ads.txt lists Google AdMob, OpenX, Sovrn, Yahoo, Magnite (Rubicon), PubMatic, DSP Exchange.

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