As part of the Rearc initiative, IAB Tech Lab is adding an additional measure of transparency to the supply chain with id-sources.json.

Today, different systems, platforms and products across the digital ad supply chain offer advertisers, agencies, ad technologies and publishers with unique-to-users identifiers (“IDs”) to support a range of addressability outcomes. Without knowing which businesses support which ID sources, engineers, ad ops, and compliance organizations spend unnecessary time and resources to understand who can transmit and process what. Having a standard way to identify who is built to support and transmit various ID sources simplifies these problems and creates opportunities for cleaner records and better analysis.

The id-sources.json object is provided in a predictable structure and is populated with the ID sources a business uses. Like other transparency standards, it is stored at the root domain for easy access.

Released for public comment on October 13, 2021, we’d like to hear from you on the details outlined in the draft specification. Download the PDF, review and send your feedback to by November 12, 2021.

Download the id-sources.json Tech Specs (Draft in Public Comment)


Go to Rearc Page