What is supply chain transparency in CTV advertising?

Supply chain transparency in CTV means being able to verify that an impression was delivered to a real CTV device on a declared publisher app, and that every intermediary between the publisher and buyer was authorised. Without transparency controls, a buyer purchasing India CTV inventory may receive impressions from apps that falsely claim to be premium publishers, from devices that are not CTV devices, or from SSPs not authorised by the publisher to sell their inventory. These supply chain fraud risks are lower in India CTV than in web open exchange — India CTV is dominated by known publishers — but exist in the long tail of programmatic inventory and matter when campaigns extend beyond the top 5 publishers.

App-ads.txt is the IAB Tech Lab standard for CTV and app publishers to declare which SSPs and resellers are authorised to sell their inventory. A publisher hosting a CTV app on Android TV or Amazon Fire TV publishes an app-ads.txt file listing every authorised SSP with their account IDs. When a DSP receives a bid request claiming to be from that publisher's app, it checks the app-ads.txt file to verify the SSP is listed as authorised. If the SSP is not listed, the impression is flagged as potentially unauthorised. Major India CTV publishers (JioHotstar, Zee5, SonyLIV) maintain app-ads.txt files. Mid-tier and regional publishers have inconsistent adoption.

The schain (supply chain) object is a field in the OpenRTB bid request that lists every entity in the supply path from publisher to buyer — the publisher, SSPs, and any resellers — in sequence, each with a verifiable identifier. A complete schain lets the buyer trace exactly how the impression travelled from the publisher app to the DSP. DSPs like DV360 and The Trade Desk check schain completeness and can reject bid requests with incomplete or unverifiable supply chains. In India CTV, schain completeness is high for direct publisher-SSP paths (e.g., Zee5 via PubMatic); it is lower where inventory passes through resellers. Supply chain filtering via schain is one of the most effective anti-fraud controls available for programmatic India CTV buyers.