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.

ccma.cat achieves the best ad optimization: its app-ads.txt has no errors and matches what its 2 ad networks expect (100% of 4 lines).

Checked 21 Oct 2026. 84 lines, 69 unique records, 2 duplicates, 0 invalid lines, 6 ad networks detected.

Magnite (Rubicon) — accounts 17960, 22328, 22330: 3 lines in the file
Amazon Publisher Services — account 5123: 1 line in the file
Mintegral — partner (reseller) lines only: 15 lines in the file, 400 expected lines missing
Yango Ads — partner (reseller) lines only: 22 lines in the file, 400 expected lines missing
DSP Exchange — partner (reseller) lines only: 19 lines in the file, 400 expected lines missing
Bidmachine — partner (reseller) lines only: 21 lines in the file, 400 expected lines missing

Yes — https://ccma.cat/app-ads.txt has 84 lines (checked 21 Oct 2026).

Its app-ads.txt lists Magnite (Rubicon), Amazon Publisher Services, Mintegral, Yango Ads, DSP Exchange, Bidmachine.

ccma.cat achieves the best ad optimization: its app-ads.txt has no errors and matches what its 2 ad networks expect (100% of 4 lines).