IAB pushes standardized conversion APIs to close CTV outcome gap

Connected TV publishers face losing performance budgets to more measurable channels without adopting standardized Conversion APIs. The Interactive Advertising Bureau released a comprehensive guide on October 30, 2025, urging industrywide implementation of server-to-server data frameworks to transform CTV into an outcome-driven advertising channel.

The 26-page report, titled "The Role of Conversion API in Closing the Outcome Gap for CTV," draws from proprietary surveys of brands, agencies, publishers, and technology platforms. Survey data reveals 75 percent of publishers identify purchases as the most commonly implemented signal through CAPI, while 64 percent track views and 61 percent monitor add-to-cart actions.

Traditional client-side tracking methods face mounting constraints from privacy regulations and browser restrictions. These limitations create significant measurement gaps between CTV and established performance channels. Without server-to-server data flows, advertisers struggle to measure return on investment with the same precision available through search and social platforms.

Performance gains drive adoption momentum

Two-thirds of advertisers report improved return on ad spend after implementing Conversion APIs. Better attribution, cleaner data, and more efficient optimization drive these improvements. Three-quarters of advertisers indicate willingness to reallocate spending based on conversion insights, signaling CAPI already influences planning and investment decisions.

Budget fluidity matters for publishers. CTV's share of media budgets is projected to double from 14 percent in 2023 to 28 percent in 2025, with 72 percent of marketers planning to increase programmatic advertising investment. Publishers without standardized conversion tracking risk exclusion from this growth.

Optimization capabilities extend beyond measurement. CAPI enriches signals across audience targeting, which 92 percent of advertisers use, personalization at 67 percent, and creative testing at 8 percent. The technology transforms CTV into a performance channel rather than purely a reach medium.

Technical complexity blocks widespread implementation

Integration challenges top the barrier list. Seventy-two percent of publishers cite technical complexity as a major obstacle, while 61 percent identify compliance with legal and regulatory requirements as significant concerns. Server setup, deduplication logic, and cross-platform data flows demand engineering resources not always available to marketing teams.

CTV presents unique measurement challenges compared to social platforms. The ecosystem involves multiple platforms, devices, publishers, and ad servers, each operating with different standards and limited interoperability. Social media operates within consolidated ecosystems with few major platforms, making integration frameworks significantly easier to implement and manage.

User identifiers remain limited in CTV environments. Social platforms benefit from rich user profiles including email, phone numbers, and login data. CTV still faces challenges similar to linear television in capturing co-viewing behavior. Even with interactive ad formats, user engagement in CTV environments lags behind social platforms where click actions directly tie to conversion events.

Identity resolution strategies blend deterministic and probabilistic methods. Sixty-eight percent of advertisers use deterministic signals like hashed emails and device IDs for accuracy. Sixty-four percent employ probabilistic methods such as IP addresses to extend reach when direct identifiers remain unavailable.

Mid-funnel signals remain underutilized

Publishers support bottom-funnel signals but lack coverage for mid-funnel events driving consideration and intent. While purchases, sign-ups, and subscriptions receive wide support at 75 percent, 61 percent, and 50 percent respectively, mid-funnel activities lag significantly. Cart abandonment reaches only 25 percent implementation, logins 31 percent, and search actions 36 percent.

Without mid-funnel signals, publishers miss opportunities demonstrating incremental value and richer consumer journey insights. Twenty-five percent of publishers already receiving cart abandonment data matches the 25 percent explicitly wanting it but not receiving it, underscoring unmet demand for actionable signals.

CRM systems serve as the primary data source for 75 percent of advertisers implementing CAPI. Customer Data Platforms play increasingly central roles, with 58 percent of advertisers relying on CDPs to unify disparate data sources, normalize inputs, and enable privacy controls across channels.

Transparency gaps undermine trust

Only 21 percent of publishers consistently provide advertisers with access to logs or dashboards. Eighteen percent sometimes provide access, 36 percent never do, and another 25 percent remain unsure. This fragmentation creates friction for advertisers needing to troubleshoot integrations, validate performance, and build trust in received signals.

Data sharing concerns persist despite technical solutions. Seventy-two percent of advertisers express at least some hesitation about sharing conversion data with external partners. Thirty-two percent report being very concerned, citing competitive sensitivities and compliance risks. Only 17 percent report no concerns.

Trust issues extend beyond privacy regulations. Many advertisers hesitate sharing detailed sales data with external platforms even when anonymized, fearing potential misuse or dependency risks. The richer the data shared, the more effective the optimization, yet the higher the perceived risk.

Standardization offers partial relief. Fourteen percent of respondents believe standardization would greatly ease concerns, while 33 percent think it would moderately help and 29 percent believe it would help somewhat. Yet 25 percent indicate standardization would not remove all concerns, suggesting need for broader trust-building measures including secure data governance and contractual clarity.

Signal strategy splits between standard and custom approaches

Advertisers divide nearly evenly on signal strategies. Forty-six percent rely primarily on standardized signals like purchases, views, add-to-cart actions, and sign-ups enabling consistent measurement and attribution across partners. Slightly more, 54 percent, lean into custom signals such as cart abandonment recovery triggers or product-specific interactions reflecting flexibility required for unique business models.

Standard signals enable benchmarking benefits through consistent performance evaluation across partners. Custom signals allow advertisers to differentiate by aligning optimization tightly with business objectives. Both approaches remain essential, as too much customization risks fragmentation while excessive standardization limits innovation.

The IAB Tech Lab's CAPI Standardization Project addresses this balance. The specification extends beyond conversion events to capture all events advertisers find valuable for optimization or ROI measurement. By establishing shared frameworks where platforms align on event taxonomies and consent metadata, the project lowers operational burden for advertisers while making deployment scalable.

Ownership patterns favor in-house control

Two-thirds of advertisers manage CAPI implementation in-house to maintain tighter control over data flows. Twenty-five percent leverage technology partners, while agencies play only limited roles at 8.3 percent. This trend signals broader industry shifts toward in-housing critical data functions to safeguard privacy, maintain flexibility, and enable faster optimization cycles.

LinkedIn reported that CAPI users achieve 20 percent lower cost per acquisition and 31 percent more attributed conversions compared to standard implementations. The platform's Conversions API enables 64 percent of companies to optimize campaigns toward pipeline conversions and revenue rather than top-of-funnel metrics.

Technology partners bridge integration gaps between advertiser systems, publishers, and ad platforms. Customer Data Platforms, tag managers, clean room providers, and large integrators reduce complexity for advertisers. These partners automate server-side event collection, enrich signals with identity and consent metadata, ensure privacy regulation compliance, and scale integrations across multiple publishers.

Optimization use cases span the full funnel

Sixty-one percent of publishers use CAPI for bidding optimization, feeding conversion and audience data directly into bidding algorithms. Half report using it for audience segmentation, enabling precise targeting and retargeting by building segments like purchasers, subscribers, or cart abandoners.

Upper-funnel applications show growing adoption. Sixty-four percent of publishers use CAPI for audience targeting, leveraging privacy-safe conversion and engagement signals to strengthen precision marketing. Seventy-nine percent optimize live campaigns at the mid-funnel stage, making adjustments improving efficiency and impact.

Bottom-funnel applications demonstrate firm establishment. Sixty-eight percent use CAPI for conversion tracking, 75 percent for performance measurement, and another 75 percent for attribution modeling. These applications ensure outcomes capture with accuracy, campaigns evaluate against business results, and credit properly assigns to channels and partners driving success.

Creative optimization remains nascent. Only 8 percent of advertisers rotate or test creative based on server-side signals, revealing untapped innovation areas. By extending signal-driven optimization beyond audiences and bidding into creative decisioning, advertisers can unlock holistic feedback loops ensuring not only who sees ads but what they see informs from real performance data.

Multi-method measurement ensures signal resilience

CAPI rarely implements in isolation. Sixty-seven percent combine CAPI with pixels to ensure redundancy and broader signal coverage. Forty-two percent support SDK integrations for in-app and mobile environments. Seventeen percent use third-party attribution tools, while only 8 percent rely on CAPI alone.

This hybrid approach reflects strategic priorities: maintain signal resilience through multiple pathways while migrating toward futures where first-party data becomes measurement backbone. As Yahoo DSP's Conversion API demonstrated with technology advertisers seeing three times more attributed conversions across different channels and devices, server-side tracking overcomes cookie limitations.

Privacy frameworks provide essential foundations. The IAB Tech Lab's Global Privacy Platform and Transparency & Consent Framework standardize user permission management across regions. Modern encryption, token protections, and OAuth-based access safeguard sensitive data during transmission. ISO privacy and security certifications establish partner accountability.

Path forward requires collaborative action

The guide includes a five-step implementation checklist. Organizations should identify key signals aligning with marketing objectives, set up server infrastructure to capture conversion events and hash user identifiers, integrate with CTV platforms ensuring proper event mapping, coordinate with legal and privacy teams for GDPR and CCPA compliance, and align creative IDs with conversion tracking for performance analysis.

David Cohen, IAB's CEO, emphasized urgency in the announcement: "The industry has been very consistent with advertisers signaling loud and clear that outcomes matter. This report is a call to action. Without standardization and implementation of CAPI, CTV platforms will struggle to reach their full potential, and will lose performance budgets to more measurable channels."

Jamie Finstein, Vice President of IAB's Media Center, added context: "Advertisers want streaming, and they need accountability. A standardized CAPI is how CTV can deliver both."

The IAB released a companion decision tree helping organizations assess readiness for server-side data integrations. The framework simplifies decisions across data quality, technical integration, organizational alignment, and campaign optimization by offering clear pathways and remediation steps.

Survey methodology drew from anonymous responses fielded between July 22 and August 19, 2025. The sell-side survey included 28 publisher and ad tech platform companies. The buy-side survey captured 17 advertiser and agency companies across sizes ranging from small and mid-size through large organizations exceeding 10,000 employees.

Timeline

• October 30, 2025: IAB releases comprehensive guide urging standardized Conversion API adoption for Connected TV
• October 23, 2025: Teads launches deterministic CTV measurement solution tracking site visits and conversions tied to streaming exposure
• August 19, 2025: Kargo CTV campaigns demonstrate 78% higher attention rates than industry benchmarks through Enhanced Branded Canvas format
• July 30, 2025: Criteo and WPP Media launch commerce-driven CTV activation combining real-time commerce signals with premium inventory
• May 3, 2025: Yahoo DSP unveils Conversion API addressing measurement challenges in cookieless environments
• November 28, 2023: LinkedIn introduces Conversions API enabling B2B marketers to connect offline and online data

Summary

Who: The Interactive Advertising Bureau surveyed 28 publisher and ad tech platform companies alongside 17 advertiser and agency companies across various sizes to inform this guide for brands, agencies, publishers, and technology platforms.

What: IAB released a 26-page guide showing how standardized Conversion APIs can enable Connected TV to match the outcome measurement capabilities of search and social channels through secure server-to-server data transmission, with two-thirds of advertisers reporting improved ROAS after implementation.

When: The guide was released on October 30, 2025, based on survey data collected between July 22 and August 19, 2025, as CTV's media budget share projects to double from 14 percent in 2023 to 28 percent in 2025.

Where: The research examines the global digital advertising ecosystem with particular focus on Connected TV measurement gaps affecting publishers, advertisers, and technology platforms worldwide.

Why: Without standardized Conversion APIs, CTV platforms risk losing performance budgets to more measurable channels despite 72 percent of marketers planning to increase programmatic investment, as fragmented ecosystems, limited user identifiers, and lack of direct engagement signals prevent CTV from demonstrating the same accountability as search and social platforms.