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.

mapmyrun.com achieves the best ad optimization: its app-ads.txt has no errors and matches what its 6 ad networks expect (100% of 19 lines).

Checked 19 Oct 2026. 152 lines, 126 unique records, 1 duplicates, 0 invalid lines, 8 ad networks detected.

Google AdMob — account pub-7518498320451544: 1 line in the file
Index Exchange — accounts 209795, 191480, 198020 and 2 more: 5 lines in the file
Magnite (Rubicon) — accounts 18254, 18252: 2 lines in the file
OpenX — accounts 541075641, 561472292, 561340792 and 3 more: 6 lines in the file
PubMatic — accounts 167466, 167467, 167465: 3 lines in the file
TripleLift — accounts 6906, 8470: 2 lines in the file
BIGO Ads — partner (reseller) lines only: 10 lines in the file, 400 expected lines missing
Bidmachine — partner (reseller) lines only: 21 lines in the file, 400 expected lines missing

Yes — https://mapmyrun.com/app-ads.txt has 152 lines (checked 19 Oct 2026).

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

mapmyrun.com achieves the best ad optimization: its app-ads.txt has no errors and matches what its 6 ad networks expect (100% of 19 lines).