Aiming to ensure online ad businesses are better equipped in the post-cookies world, in October 2021 IAB Tech Lab introduced its new tech specification, id-sources.json. Here’s what you need to know about it. 

As explained in the official announcement, the IAB Tech Lab’s id-sources.json specification is primarily designed to facilitate digital ad businesses, allowing them to achieve higher transparency, regarding their partners’ customer ID usage across the supply chain. 

Simply put, the key idea behind id-sources.json implies the adoption of a universal approach to the declaration of various user identifiers, applied for online ad purposes, which is likely to grow significantly crucial upon the deprecation of third-party cookies. 

Benefits of id-sources.json Adoption

From brands’ and agencies’ perspective, the market-wide implementation of id-sources.json will enable them to map out the identifiers their partner publishers utilize and compare these against their proprietary audiences (i.e. corresponding to the other type/s of identifiers). 

Consequently, this will equip them with new, practical methods to find and activate their addressable audiences more effectively, and adjust their video ad campaign settings, accordingly, in order to achieve maximum customer reach and engagement. 

As for the key benefits for publishers, the adoption of id-sources.json should, quite predictably, act as yet another proof of their inventory quality, and help maintain their business reputation as reliable Supply partners. 

How to Implement id-sources.json

Blame it on the success of the previously released tech specifications, like sellers.json and buyers.json, that this time IAB Tech Lab took a similar approach while developing id-sources.json. 

Namely, the specification implies the creation of the id-sources.json file enlisting sources of user identifiers a publisher is working with, and making it available on their ad domain in a machine-readable format (e.g.

Note! Similar to the case with ads.txt, the mentioned URL is an example, used for illustrative purposes, so visiting it will yield no result.

The parent object in the id-sources.json file includes three key elements (all required), i.e.:

  • sources (object array) – enlists all the integrated source objects; 
  • version (string) – provides info on the version of the specification;
  • last_updated (datetime) – defined the time and date of the latest update of id-sources.json

The parent object may also include contact details (contact_email), but this attribute is optional.

Meanwhile, the source object itself includes the following attributes, all required: 

  • source (string) – a value referencing the domain provider of a user ID source;
  • name (string) – the business name of the user ID (e.g. idfa);
  • transformation (true/false) – defines whether the user ID source underwent any change prior to its provision.

In case the transformation attr. value is true, the following attribute is also mandatory for adding in the sources object:

  • transformation_methods (array of enums) – defines how exactly the user ID source was transformed, if so (e.g. whether it was decrypted, hashed, turned into a deal or a segment ID).

When to get started with id-sources.json 

Even though the perspectives of the global adoption of the new tech specification are rather optimistic so far, a smart publisher’s move would be to plan its adoption for 2022, while focusing on the more urgent matters in December 2021, like fine-tuning your monetization strategy, in order to finish up the year with maximum revenue results. 

For more information about id-sources.json, please refer to IAB Tech Lab’s implementation guide.