Facebook Conversion API (CAPI): The Future of Tracking on iOS 14

Since early 2021, the changes brought by Apple’s App Tracking Transparency framework on iOS 14 have made it harder for advertisers to collect data on Facebook. The Facebook Conversion API (formerly Server-Side API) could offer a glimmer of hope in a world full of ad blockers. How exactly it works—and whether it can truly combat the data blackout—is what you’ll find out here.

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What To Expect

• What is a Conversion API, anyway?
• Benefits of the Conversion API
• What Should You Keep in Mind When Using the CAPI?
• Recommendation for Your Facebook Tracking Setup
• Conclusion

Since 2021, changes to Apple’s App Tracking Transparency framework on iOS 14 have made it significantly harder for advertisers to collect data on Facebook. When users opt out, events are only aggregated in a limited way and reported with delays. For most advertisers, “business as usual” is no longer an option—they’re seeing far less data to base decisions on for optimizing and scaling their campaigns. The Facebook Conversion API (formerly Server-Side API) is now seen by many as a small glimmer of hope in a world dominated by ad blockers.

What is a Conversion API, anyway?

The Conversion API (CAPI) is a server-side method of website tracking. It collects data directly from your server and sends it to third-party tools—such as Facebook or Google Analytics. The basic principle is essentially the same as pixel-based tracking. The key difference is that the data isn’t collected by the user’s browser or app, but by your server and then passed on.

So, it’s not exactly a revolutionary concept. In fact, server-side tracking has long been used—for instance, to measure offline purchases.

But if the Conversion API isn’t something entirely new and essentially works like the pixel, how exactly does it help solve our data collection problem?

As shown in the graphic, the CAPI is an additional tracking tool designed to work alongside the traditional pixel tracking. Below, we’ve summarized the key advantages of this setup and the new insights that can be gained from using the Conversion API.

Benefits of the Conversion API

For advertisers, using the Conversion API alongside the Facebook Pixel offers significant advantages. Not only does the CAPI capture more data signals than the pixel alone, but it also proves to be far more stable when it comes to issues that can affect conversion data.

Here’s an overview of the key benefits:

• Ad blockers: The Conversion API helps bypass browser-based ad blockers.
• Conversion data reliability: Less vulnerable to disruptions like browser crashes, connection issues, or long page load times.
• Algorithm & optimization: Provides more data signals to feed the algorithm and improve campaign optimization.
• Audience building: Enables better audience creation (retargeting and lookalike audiences) through richer data.
• Attribution: Delivers more data signals for improved attribution accuracy.
• Offline events: Allows tracking of offline conversions, such as phone calls or in-store purchases.

What Should You Keep in Mind When Using the CAPI?

Despite all the benefits the Conversion API offers, there are a few important aspects to consider when implementing and using it:

1. Implementation: The Conversion API is a technically complex solution, and in most cases, you’ll need an expert to implement it correctly. It’s crucial to thoroughly test whether all data is being received reliably.
2. Data Privacy: Data protection regulations still apply. Without the proper legal basis and user consent, it remains prohibited to track personal data. This means GDPR-compliant consent management is still essential.

Recommendation for Your Facebook Tracking Setup

If your company has the necessary resources, definitely implement the Conversion API in addition to the Facebook Pixel. The added data signals (such as offline events) and more stable results will pay off in the long run.

Thanks to the combined use of CAPI and Pixel, upper-funnel events can still be tracked reliably.

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Conclusion

The Conversion API isn’t brand new—but due to the complex setup, there are still relatively few real-world examples and case studies. Implementing it alongside the Facebook Pixel can help you gain more visibility into your campaign data in Ads Manager. And more data always means more room for optimization, giving your ROAS the potential to reach top levels.

Ad blocking is just getting started—and it’s far from over. That’s why now is the time to experiment with alternative tracking methods like the CAPI to future-proof your tracking setup.

👉 The Conversion API isn’t a replacement for the Pixel—but it’s definitely a key part of Facebook tracking going forward.