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.

m51.co app-ads.txt check

m51.co is missing out on higher CPMs: its app-ads.txt has 1 invalid line. Buyers' crawlers skip invalid lines, so those sellers can't be verified.

Checked 20 Oct 2026. 191 lines, 174 unique records, 9 duplicates, 1 invalid lines, 10 ad networks detected.

Ad networks in m51.co/app-ads.txt

Google AdMob — account pub-1466027582507864: 1 line in the file
OpenX — accounts 540646187, 540834345: 2 lines in the file
Magnite (Rubicon) — account 21310: 1 line in the file
Xandr (Microsoft) — account 9684: 1 line in the file
PubMatic — account 158753: 1 line in the file
Sovrn — accounts 269217, 240498: 2 lines in the file
Index Exchange — account 190549: 1 line in the file
Yango Ads — partner (reseller) lines only: 15 lines in the file, 400 expected lines missing
DSP Exchange — partner (reseller) lines only: 10 lines in the file, 400 expected lines missing
Bidmachine — partner (reseller) lines only: 15 lines in the file, 400 expected lines missing

Invalid lines

Limpid, 20351, DIRECT

Corrected file: m51.co app-ads.txt (fixed).

FAQ

Does m51.co have an app-ads.txt?

Yes — https://m51.co/app-ads.txt has 191 lines (checked 20 Oct 2026).

Which ad networks does m51.co work with?

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

Is the app-ads.txt of m51.co correct?