Conversion APIs, or CAPIs, are not a new technology, but they’re picking up in popularity. Here’s what they are and how you can use them to alleviate signal loss and utilize real purchase data to measure campaign effectiveness. 

CAPIs have been around for over five years. Meta first introduced a CAPI as a product in 2018, but the solution has been gaining steam as advertisers have increasingly searched for ways to combat signal loss. Apple’s App Tracking Transparency (ATT) framework which was rolled out in 2021 was the first real chip to fall, encouraging even more wide adoption of CAPI.

In the years following ATT, the industry has been subject to constant Google whiplash, in addition to increasing privacy legalization at the state and federal level. More ad platforms realized that advertisers were desperate for ways to measure, and started offering CAPIs as a solution to stay competitive and maintain clients when their ability to measure was being threatened. 

Here’s a breakdown of what you need to know. 

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What’s a Conversion API, aka CAPI, and Why Use Them? 

A CAPI is a server-to-server connection that allows advertisers to send conversion event data (like purchases, sign-ups, and other actions) directly from their server to an ad platform’s server. Unlike traditional browser-based pixel tracking, CAPIs provide a more robust, reliable, and privacy-friendly approach to tracking conversions.

CAPIs can act as a replacement to pixel-based conversion tracking which relies on cookies and other non-privacy safe identifiers. They solve for signal loss by sending data securely and directly from servers instead of relying on cookie-based identifiers to match users to impressions to measure attribution. 

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How Do They Work? 

Brands can send first-party data to a CAPI from their own servers or from their customer data platform (CDPs). Brands will need to integrate with each platform separately, which can mean a decent amount of technical overhead. Platforms can accept different data fields from brands that will enable either deterministic or probabilistic matching. Once integrated, platforms can begin sending back impressions mapped to conversions. 

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Who Offers CAPIs? 

Meta, SnapChat, Pinterest, Google, TikTok, Amazon, LinkedIn, Reddit, and Nextdoor are all endemic platforms that offer CAPIs. Programmatic platforms like The Trade Desk also offer measurement partnerships utilizing a conversion API.

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What Data Does a Brand Need? 

The classic CAPI setup typically relies on brand first-party data being sent to the ad platform’s servers. Impressions from the ad platform are then matched to conversion events from the brand via a privacy safe identifier such as hashed email. If hashed emails are not available, probabilistic matching can be conducted via signals such as IP address, location, browser type, and timestamp. Sales or conversion data is also typically provided by a brand in order to enable attribution. 

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What If A Brand Has Limited First-Party Data? 

CAPIs are a great way for brands with historically limited access to purchase data, such as CPGs, to partner with alternative purchase data partners to tie impressions to sales. For example, a candy brand could work with a SKU-level purchase data partner to gain access to sales data for their product. The data partner sends the brand’s purchase data to the ad platform to match impressions back to sales.  

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To learn more about how you can work with Attain to utilize CAPI for purchase data and measurement across ad platforms, reach out to sales@attainoutcomes.com.