Nimble Digital

The Rise of Conversion APIs

Part 1

Conversion data is the lifeblood of the digital advertising ecosystem. Facebook introduced their web pixel back in 2012 to capture website interactions or browser events (ex: product views, add-to-cart, check-out, etc.). In turn, conversion data not only powers ad reporting but is also the primary engine for follow-up marketing actions, including ML audience optimization and dynamic ad targeting for potential customers.

At its core, conversion data is used to track conversions from ad platforms to optimize future ads, build custom audiences, and remarket to people who have already taken some kind of action on your website or app.

In the past, the primary way to share conversion data was through a Facebook Pixel (i.e. a web pixel), which leverages third-party cookies to share data back to Meta (Facebook) directly from browser Pixel events.

New landscape

However, in recent years, changes in consumer privacy laws (GDPR, CCPA), web browsers initiatives (ITP) , iOS and Apple privacy frameworks (ATT) as well as the rise of ad blockers have all dramatically limited the ability to collect conversion data and customer actions from web pixels.

In a recent article Meta formally acknowledged the extent of this problem, estimating that it underreports iOS web conversions by approximately 15%. Knowing this, Meta goes on to elaborate that all advertisers should turn to server-side tracking and utilize the Meta Conversion API (Facebook CAPI) to capture lost event data as a replacement to its tracking pixel.

Meta has been the loudest advocate about their Conversion API but nearly every other major advertising platform has been equally affected by privacy changes and most are introducing their own flavor of conversion APIs – Google Enhanced Conversions, Snapchat Conversions API, and TikTok Events API. These APIs give you a lot of advantages in terms of improved match rate and faster websites and applications due to fewer client side scripts.

Server Side Tag Management System

Often the task of implementing the overall conversion and measurement solutions falls on the web analyst or implementation specialist with a deep knowledge of tag management systems (TMS) such as Google Tag Manager, Tealium and other TMS. This results in a solution architecture based on a server side TMS without considering other options such as a customer data platform or building a proper marketing data warehouse.

Most sites are already running some type of tag management system making adding a server side TMS from the same provider a relatively small effort compared to setting up a customer data platform or marketing data warehouse from scratch.

For best results it’s recommended to have a redundant event setup. Redundant event setup means that, if you share the purchase, initiate checkout and contact events using the pixel, those same web events are also collected server side using the Conversion API. Redundant setups are useful because the Conversion API allows you to collect data that the pixel may lose and vice versa. Hence data accuracy and completeness will be maximized.

However, a redundant event setup comes with the issue of event duplication, since events will be collected from both the pixel and the API. Hence deduplication of all events is a necessity or you will have serious data quality issues. Here the server side TMS excels since there is a direct connection between the client side and server side TMS. This makes the deduplication processes fairly straightforward as it can be achieved automatically through these direct connections, i.e. common event IDs.

But it doesn’t end there. By providing additional customer information through the Conversion API the quality of an event match, i.e. how good an event matches to an account, can be measured and hence improved upon. This in turn helps to achieve increased conversions and lower cost per result and increasing effectiveness.


Conversion APIs will add a new lifeblood to your digital advertising ecosystem!

They can be set up fairly easily within the same provider as your pixels. The combination of these Conversion APIs and pixels reports more robust tracking data now and in the future, with an increasing number of users on iOS 14 and more restrictive browsers.

Furthermore they can be used to track additional customer information. In essence the more events are shared and the more pixels are connected to Conversion APIs the more data is available to gain improved insights. This is the new primary way to share conversion data and to fuel your ad reporting, follow-up marketing actions and dynamic ad targeting.

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