As the fragmentation of the programmatic advertising industry remains a persistent challenge for many digital businesses, particularly in the CTV ad space, conversion APIs (CAPI) are gaining greater importance in 2026. 

For what it takes, the notion of conversion APIs isn’t entirely new to the digital advertising ecosystem. However, historically it was bound to large tech platforms, particularly Meta and Google, who offered their server-to-server conversion data tracking, without a global standard in place, which could consolidate the fragmented data into a unified measurement framework for online ad campaigns, capable of improving cross-platform attribution. 

More importantly, the gradual signal loss, driven by the declining reliance on third-party browser cookies, and privacy regulations, like Apple’s ATT, in the recent years, has accelerated the industry shift to server-to-server event tracking, forcing businesses to reassess their existing measurement strategies and adopt new approaches to campaign optimization. 

Here’s where CAPI has come into the spotlight, offering a more efficient and privacy-preserving way to transmit conversion data, compared to the formerly conventional conversion tracking methods, like pixel tracking, for instance.

CAPI Grows More Widespread in CTV

One of the significant market shifts in 2026, particularly when it comes to the use of CAPI, is its growing adoption by CTV vendors and publishers, where the lack of closed-loop measurement capabilities has been a pain point for years.

In this respect, a notable example is Roku, which has been offering its CAPI for some time, aiming to help its advertising partners to improve video ad targeting and measurement precision, while giving them greater control over the scope of data shared with the platform.

Another one comes from the video streaming market, where leading players such as Netflix, have also released their proprietary CAPI capabilities. By enabling advertisers to connect their own conversion data with Netflix Ads platform insights, Netflix CAPI promises enhanced attribution measurement, helping brands to analyze their video ad campaign effectiveness more accurately, and optimize them in a more seamless way. 

The said two examples serve as clear evidence of an accelerating trend, suggesting that more companies working in CTV advertising are likely to roll out their CAPI solutions in Q3 and Q4 2026. 

What is IAB Tech Lab’s ECAPI?

While the accelerated adoption of CAPI across the CTV ad sector offers significant benefits for brands and ad agencies, until recently, the industry has lacked a unified standard for labeling and passing conversion events from advertisers to video ad platforms server-side. This has inevitably led to increased operational overhead in terms of technical implementation, while also contributing to the ongoing measurement fragmentation issues.

The good news is that starting from Q2 2026, the situation is expected improve, now that IAB Tech Lab has finalized its Event & Conversion API (ECAPI), specifically designed to standardize S2S event and conversion signal transfer from advertisers to ad tech platforms and supply-side partners, helping to streamline video ad campaign measurement and optimization across the ecosystem.

The new standard covers a wide range of supported conversion event types (from ad impressions to product searches, cart updates, purchases, signups and subscriptions, and many more), as well as an extensive set of user data tracking parameters, available for passing across the digital ad supply chain. The core of ECAPI, however, is built around the two key parameters, i.e. data_set_id (usually an advertiser’s ID or ad account ID, required) and id (a unique event ID, highly recommended). 

Namely, if a passed event record matches both parameters, it’s assumed to be treated as the same, single event. Meanwhile, if the same event ID is passed with different Data Set IDs, it should be referred to as unrelated, unique events. 

If the same event is recorded across multiple sources (CAPI, tracking pixel), the same event ID should be passed. However, if there’s no guarantee that the same, unique event ID is actually being passed from the said sources, it’s recommended to omit the event ID to avoid discrepancies. 

Is ECAPI a Quick Fix for the Existing Measurement Gap?

As seen from a wider perspective, what makes the ECAPI standard stand out is its promised relative simplicity of adoption by advertisers, who are expected to map their existing event tracking data to the new framework, hence ensuring the more streamlined workflow. And on the supply side, it doesn’t require the complete rebuilding of conversion data processing infrastructure either.

At the same time, the ECAPI documentation explicitly declares the necessity to handle the implementation and access to ECAPI with each ad tech vendor and/or partner separately, depending on their existing tech stack, which actually means that the actual adoption process isn’t as straightforward as one may expect. 

In view of this, despite high market expectations for ECAPI, adoption of the standard will probably lag throughout 2026, except among the top-tier businesses, who historically have greater operational and financial resources, inevitably required for implementation. The situation may improve in 2027, but only if driven by the consolidated efforts from large CTV players, which is yet to be seen.