Yahoo's conversion API aims to solve measurement hurdles in cookieless world

Five days ago, on April 28, 2025, Yahoo DSP unveiled its Conversion API (CAPI), addressing a significant challenge for digital marketers: accurately measuring campaign effectiveness across increasingly fragmented digital environments. The solution arrives as the industry continues adapting to diminishing third-party signals and stricter privacy regulations.

Yahoo CAPI enables advertisers to send conversion events directly to Yahoo DSP through a centralized integration point, unifying online and offline conversion data streams. This centralized approach streamlines measurement and attribution processes that traditionally required separate workflows.

At the core of Yahoo CAPI is Yahoo ConnectID, which provides addressability through 232 million logged-in users in the United States, according to information provided in Yahoo's announcement. This identity foundation aims to deliver more precise attribution in environments where cookies and advertising IDs are unavailable.

"Yahoo DSP is committed to helping advertisers navigate the evolving digital landscape with solutions that prioritize both accuracy and privacy," said Giovanni Gardelli, VP of ads data products at Yahoo. "With the launch of Yahoo CAPI, advertisers gain more control and flexibility in how they share conversion data, ensuring optimal measurement and performance."

The announcement comes during a pivotal transition period for digital advertising. Industry observers have noted the increasing difficulty of tracking conversions as browser privacy changes and regulatory shifts continue reshaping how consumer data can be collected and utilized.

Marco Parente, Director of Product Management for Measurement & Identity at Yahoo DSP, emphasized the central role of measurement in digital advertising's value proposition. "Measurement is the backbone of digital advertising - a statement every advertiser can agree with. It's what originally set digital media apart from traditional formats, where measurement often fell short," Parente stated.

According to Yahoo, initial implementation results have shown notable improvements in attribution capabilities. The company reports that a technology advertiser using CAPI to pass hashed email addresses for subscription sign-ups saw three times more attributed conversions across different channels and devices that would have been harder to measure due to lack of cookies or advertising IDs.

Similarly, a financial services advertiser reportedly experienced a fourfold increase in attributed conversions using the same approach. For commerce media specifically, Yahoo claims advertisers have seen a 30-50% increase in attributed conversions.

The technical implementation of Yahoo CAPI follows a privacy-centric design approach. Advertisers can analyze conversion data through direct integration or via LiveRamp's data collaboration platform, which serves as Yahoo CAPI's initial integration partner. This connection allows advertisers to link offline conversions with online campaign exposures.

Travis Clinger, Chief Connectivity & Ecosystem Officer at LiveRamp, highlighted the practical applications: "Through this solution, advertisers can easily upload their LiveRamp offline conversions on Yahoo DSP and close the loop on measurement, gaining a clearer understanding of how our online advertising efforts are driving offline sales."

The Yahoo CAPI solution features several technical components designed to address specific measurement challenges. It provides a single integration point for all conversion data types, including website, application, and offline sales information. Advertisers can transmit data using their own first-party identifiers or integrate through partners like LiveRamp.

The system is built around Yahoo ConnectID, which the company describes as "privacy-safe," to ensure security and compliance with privacy regulations. For commerce media specifically, CAPI powers both offline and online conversion tracking, allowing advertisers to optimize campaigns down to the product level.

The solution also works in conjunction with Yahoo's existing measurement tools. When paired with Yahoo In-Flight Outcomes, campaigns can be automatically optimized using Yahoo Blueprint Performance, an AI model designed to optimize performance while maintaining efficiency.

This launch forms part of Yahoo's broader identity strategy. The company's approach to identity includes both addressable solutions through Yahoo ConnectID and non-addressable solutions through Next-Gen Solutions, an AI technology designed for environments where traditional identity signals are unavailable.

According to information on the Yahoo Identity Solutions web page, the company maintains "a loyal user-base of consenting, authenticated users across Yahoo media properties and partners" to power its identity offerings. Yahoo also emphasizes interoperability, stating that its solutions work with "35+ major CDPs/DMPs for seamless targeting and measurement."

The current state of digital advertising measurement presents significant challenges for marketers, particularly as third-party cookies phase out and privacy regulations increase. Solutions that can accurately attribute conversions across channels, especially connecting online advertising to offline sales, have become increasingly important for demonstrating return on investment.

The Yahoo CAPI launch marks a significant technical development that may particularly impact commerce media networks and retailers building advertising businesses. By providing a mechanism to link offline sales data with online ad exposures, these businesses gain additional measurement capabilities to demonstrate value to advertising partners.

For the broader marketing community, this development signals continued industry focus on developing measurement solutions that balance accuracy with privacy considerations. As advertisers face increased pressure to demonstrate return on investment amid economic uncertainties, tools that provide more comprehensive conversion data may help justify digital advertising budgets.

Yahoo's approach also reflects the general industry direction toward first-party data strategies and privacy-centric measurement solutions. The ability to process offline conversion events alongside online activities represents a technical capability that addresses specific gaps created by the deprecation of third-party tracking mechanisms.

The effectiveness of such solutions ultimately depends on scale and adoption. With Yahoo reporting 232 million logged-in users in the US, the company appears to have significant identity coverage to support its measurement claims. However, the competitive landscape for identity solutions remains crowded, with numerous technology providers offering alternative approaches.

For marketers evaluating measurement partners, the technical integration requirements and potential lift in attributed conversions will likely serve as key decision factors. Yahoo's reported results of 3-4x increases in attributed conversions for some advertisers suggest potentially significant improvements in measurement coverage, though actual results would vary based on implementation specifics and campaign parameters.

As the digital advertising ecosystem continues adapting to privacy changes, solutions that can accurately attribute conversions while respecting consumer privacy preferences will remain essential to maintaining advertiser confidence in digital channels.

Timeline

• April 28, 2025: Yahoo DSP officially announces the launch of Yahoo Conversion API (CAPI)
• March 11, 2025: Yahoo publishes several articles about identity solutions, including integration with Privacy Sandbox
• Early 2025: Yahoo reports initial testing results showing 30-50% increases in attributed conversions for Commerce Media
• 2024: Marco Parente joins Yahoo as Product Director leading measurement and identity products
• Ongoing industry context: Continuing deprecation of third-party cookies and advertising IDs across digital environments
• Current status: Yahoo CAPI available with initial integration partnership with LiveRamp for offline conversion data