Cookieless World

Google Shares FLEDGE Specification for the First Origin Trials

Google's FLEDGE
(Last Updated On: September 26, 2023)

Just two days after publishing Topics API, Google shared more details about the FLEDGE API specification for the upcoming Origin Trials. It is definitely a positive move, as it improves the industry’s understanding of the scope of tests that will be possible in the upcoming months. The specification includes essential features for advertising efficiency and utility, such as those created by RTB House – Product-level TURTLEDOVE and Outcome-based TURTLEDOVE. Sadly, the testing phase timeline hasn’t been updated for months now, so a more detailed timeline is still unavailable.

In this article you will learn about:

  • A detailed clarification of the intentions behind Origin Trials
  • The pieces that made it into the Origin Trials specification
  • The questions that arise with regards to the Trials start

The explainer itself provides a lot of clarification into the intentions of Origin Trials, showing that they aim to give developers the tools to accurately measure its utility and technical limitations. Google explicitly states that many of the elements included in the full FLEDGE specification, will not be available within the first Trials. To name some of the most important: Fenced Frames, which are supposed to replace traditional iframes; Aggregated Reporting API, serving as a tool for understanding campaign outcomes from the business perspective; and k-anonymity limitation, for ensuring privacy protection. Also, the initial Origin Trials will not be available on mobile devices, and will not allow for delegating interest groups to third parties. It is also uncertain what percentage of Chrome traffic will be included in these Trials.

On the upside, many important pieces made it into the specification, which RTB House created and championed for:

  • Product-level TURTLEDOVE – a proposal for the improvement of product personalization,
  • Outcome-based TURTLEDOVE – a proposal for the improvement of bidding efficiency,

We are pleased that our contribution – in the form of tools that have a measurable impact on the efficacy of advertising, and at the same time protects the privacy of users – is an integral element of the tested solution.

It’s worth noting that Google singled out our work on its blog:

RTB House’s Outcome-based and Product-level TURTLEDOVE modifications improved the anonymity model and personalization capabilities of the on-device auction.

Moreover, we believe that including multi-ssp auctions is a positive move, as it will allow for headerbidding support and invite the Prebid community to take the initiative. As an active member of, and an entity with a bidding system supporting FLEDGE end-to-end, we are open to assisting Prebid in the FLEDGE tests. Also, making an opt-in mechanism as a default for publishers gives them more control over who will take part in the auction through auction configurations. It improves the transparency of the buying channels compared to the current state, which is beneficial for publishers. This move is also in line with the IAB Tech Lab proposal on buyers.json.

While RTB House is positively responding to Google’s publication, we acknowledge that some questions remain unanswered, i.e. when will the Trials start, what share of internet traffic will be included. It is also important to remember that it is still unclear how browser-side resource management will work – what will be the split of computational power between the buyers? Specifically, what will the browser do if there are too many interest groups for evaluation? 

It will definitely be a challenge to ensure a level playing field in this matter, between all the entities, regardless of their size, especially since the arbitration will be performed by the entity owning browser, ad server, DSP, and SSP under the same roof.

If you have any questions, comments or issues, or you’re interested in meeting with us, please get in touch.

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