But everything will change after the iOS14 privacy update. And even though Facebook Pixel is laying on a deathbed, there is an alternative that might be promising more results than you expect from it.

Without further ado, let’s learn what CAPI is, why you have to use it and how to apply it for peak performance! 

A quick recap: why did Facebook rules change? 

Digital space hasn’t been at its best health in the past couple of years, so the regulatory system started intervening.

The GDPR (General Data Protection Regulation) came into effect in 2018, which forced advertisers and website owners to notify users about the usage of cookies and tracking of the personal information about them.

Even before the law was adopted, Apple made a first move by restricting the third-party cookies on Safari web browser. Then Firefox and Edge followed Safari down the cookieless road.

However, 2020 and the iOS 14 update was way more painful, with the option opt-out of in-app tracking. 

Facebook lost an incredible amount of data to feed its algorithms and had to quickly adapt. 

But as we can see, Facebook adjustments covered a much broader array of events than just mobile-tracking: 

  • Requirement to verify domain for authentication purposes
  • Attribution window decreased to seven-day from 28-day
  • Facebook Conversion API as a necessity for proper performance
  • NEW: Facebook Analytics is preparing for retirement 

Clearly, Facebook is getting ready for the new era of advertising. No matter how loud the fights are in the media between Apple and Facebook, it’s fair to say that Facebook would have to do it anyway. Maybe now is just the right moment to make the jump? 

What is the Facebook Conversion API and how can you season it? 

Facebook Conversion API is a server side tracking and attribution technology. Unlike Facebook Pixel, that worked on a browser side, CAPI tracks all events server to server. 

Facebook Pixel is a trusted technology, but it’s becoming outdated in the age of cookieless updates. On the other hand, Facebook CAPI existed even before, but was more of a fancy technology for pro marketers or giant advertising companies.

Disadvantages of a Facebook Pixel 

  • Doesn’t comply with Privacy Updates
  • Provides inaccurate attribution and conversion data
  • Gets easily blocked by ad blockers

Advantages of a Facebook CAPI 

  • Futureproof for cookieless updates
  • Better accuracy for conversion data
  • Better attribution

Facebook Pixel still works, and Facebook CAPI works perfectly too. But a way to transfer the data to FB algorithms for optimisation is tricky. The best decision right now is to partner up the forces of Facebook Pixel and Facebook Conversion API. Why? 

The partnership of Facebook Pixel and Facebook Conversion API

Facebook Pixel is still responsible for gathering all the data inside of the platform. And CAPI is there to cover the server side tracking, in order to ensure the ability to do the tracking and attribution in a safe way for the digital space. When these two are together, they are a real power couple. 

You get the data, track on a server side, attribute conversions and optimise the campaigns towards an event of your choice (like a purchase, sign-up, clicks, etc.). 

However, there are two very important things that you have to follow: 

  • You can optimise only for the events added to the Aggregated Events Measurement (AEM)
  • You can add events to AEM only once they are “warmed-up”
  • You can configure events only coming from verified domains

Unfolding AEM

AEM is a special Facebook protocol that allows measurement of events after the iOS 14 Update was rolled out. You can add up to eight events to AEM to configure and use for optimisation of your campaigns.

Make sure to always choose the right events for top priority, because that’s what Facebook is going to be focused on.

You can not add the event to AEM until the event has got enough traction. What is ‘enough’ is a mystery, since every event was behaving differently in that regard. On average, an event has to receive from 15 to 30 conversions and always has to be associated with a verified domain. 

Domain verification 

Now it is not just a recommendation but a requirement to verify the domain where conversions happen for your events. It’s not that complicated for advertisers who own the domain, you just have to follow the Facebook guide.

There are three ways to verify domain on Facebook: 

  • DNS verification
  • HTML File Upload
  • Meta-tag verification

However, those involved in affiliate marketing are under the influence. You need to have access to the domain of the conversion event. And since affiliates run offers through the advertisers, they simply don’t have it. Therefore, affiliates need to find alternative solutions for domain verification. 

Attribution window limitations 

After the update, Facebook jumped from a 28-day click attribution window to seven day one. This is hurtful, since you put your optimisation decisions at risk due to a shorter period of time when the data has been stored. Plus, the view attribution window has changed from seven day to one day. 

It is logical to state that the more data you have, the better the attribution will be.

This data is directly influencing the way your campaign optimisation goes. And obviously the end victory is the boost in conversion/sales/clicks/etc. You have to find a way to increase the attribution window to get accurate results. 


When you choose to go for Facebook Conversion API you have two options: 

  • DIY (a developer has to code a solution for you)
  • Find a perfect mar-tech solution

The Facebook Guidelines show how you can develop a CAPI solution with your own resources. 

The benefits to look for in Mar-Tech solutions: 

  • Complex solution (goes beyond Facebook CAPI setup)
  • No-tech skills required for setup
  • Solutions for better attribution modelling
  • Helps verify third-party domains (if you are an affiliate)

To sum up, things you need to take control of when choosing Facebook Ads:

  • Implement CAPI & partner forces with Pixel
  • Verify the domain 
  • Warm-up the events and add them to AEM
  • Choose top priority events for optimisation in AEM
  • Find a solution for improved attribution

Yes, it has become way more difficult to maintain the performance that we’re used to on Facebook. If you want to receive benefits from Facebook Ads, you have to find a way to its heart. We believe that now we have entered the times when it’s better to delegate it to people who devote their time to decoding the Facebook mysteries.