app-ads.txt

app-ads.txt is the IAB Tech Lab standard that lets app developers publish a public list of the companies authorized to sell their apps' ad inventory, using the developer website named in each app's store listing.

ads.txt works for websites because the domain in a bid request points straight to the file. Apps have no domain of their own, so app-ads.txt adds a link. The developer lists a website URL in each app store listing and posts an app-ads.txt file on that domain. Verifiers crawl the store listing, find the developer URL, work out the file location and read the authorized sellers (IAB Tech Lab, app-ads.txt specification).

The file uses the same record format as ads.txt: the ad system's domain, the seller's account ID, the relationship (DIRECT or RESELLER) and an optional certification authority ID. The standard covers mobile app stores and connected-TV app stores. Sell-side platforms are asked to include the storeurl field in bid requests so buyers can map each request to its store listing. Buyers then check that the SSP and account in the request match a line in the developer's file.

Example: A game studio lists https://studio.example.com in its store listings and posts studio.example.com/app-ads.txt with the line ssp.example.com, 12345, DIRECT. A DSP that gets a bid request for the game from a different account ID treats it as unauthorized. A planned ads.txt and app-ads.txt generator will produce valid files.

Related terms: ads.txt, sellers.json, ads.cert, SupplyChain object, SSP.

Authoritative source: IAB Tech Lab, "Authorized Sellers for Apps (app-ads.txt)" specification, Supply Chain Validation repository (accessed 9 November 2026).