Unlocking the Power of Facebook's Conversions API with Segment: A Guide to First-Party Data Retargeting

Explore the shifting terrain of online privacy regulations, including Facebook's Conversions API, and learn how Segment streamlines the integration and transmission of first-party data, enabling efficient retargeting strategies.

By Segment

Are you in the 1%? Last month, Google began its roll out Tracking Protection, within its Privacy Sandbox, to 1% of Chrome users. This is the start of their long awaited initiative to remove third-party cookies from the browser and they intend to have the other 99% feel the effect before the end of year.

Internet browsers (iOS) and governments (GDPR, CCPA) are establishing an internet where:

  1. Consumer privacy comes first.

  2. Only first-party data survives.

  3. Browsers are less reliable tools to share data back to advertising platforms. 

These regulations left companies to figure out how to send relevant advertisements to their customers while remaining compliant. When iOS 14 was introduced in 2020, Meta (formerly Facebook) shared a blog post sharing their dissatisfaction.

And from their dissatisfaction, they created the Facebook Conversions API (CAPI). To quote Meta itself, Conversions API is a “business tool that helps advertisers use their own marketing data to optimize ad targeting, effectively drive organizational outcomes and more accurately measure campaign performance.”

This article will explain what Facebook’s Conversions API is, why it’s worth focusing on, and how to use Segment to collect your first-party data and sync to Facebook for retargeting. 

What is the Facebook Conversions API?

We will cover two types of tracking that come from Facebook- the pixel and the Conversions API.

The Facebook Pixel

The Facebook pixel is a long time practice for customers to run ads. They do this by installing the Facebook pixel directly on their website or by using Segment to bundle and share pixel events automatically

With this setup, when users land on a website and complete actions (such as Product Viewed, Demo Requested, etc.), the pixel collects and sends these events to Facebook directly from the browser (user’s device).

While this is a powerful way to send first-party data to Facebook, the introduction of new browser privacy policies, the death of third-party cookies, and the adoption of ad-blockers are making the facebook pixel tracking less reliable.

The Facebook CAPI

Facebook’s Conversions API is a different, yet powerful way to send your first-party data directly from your application servers (not the user’s device) to Facebook.

This type of server-side communication is extremely reliable and allows you to choose exactly what data to share with Facebook, instead of relying solely on data the Facebook pixel collects. 

The conversions API lets you send customer events and other conversion-related information without relying on cookies, and instead it relies directly from your server. This means that your company owns all of the conversion data collected.

Conversions API also allows you to share conversion events lower in the funnel that may not even take place on your website (e.g. within your app, CRM, Support Tool, etc.)

Facebook’s Conversions API x Segment’s CDP

Segment allows companies to unify customer data collection to a single API, and then streams this data anywhere without requiring additional engineering effort. 

Instead of having your engineers build one-off integrations directly with the Facebook Conversions API (and every other tool), the idea is to track your events once to Segment, and then Segment can stream these events to your entire tech stack  - Analytics, Data Warehouse, CRM, Marketing tools, as well as the Conversions API.

For any data destination, Segment will perform all the data mappings and translations, so the data is being received by the partner destination properly. For example, with the Conversions API, Segment will do relevant data mappings and hash appropriate PII, as required by Facebook.

Facebook’s official best practice is to use Segment to send web events using both the pixel and the CAPI, where the server-side events are a backup for times the client-side Facebook pixel fails. Today there are two main use-cases to implement this:

  1. More reliable website tracking: For collecting website behavior, currently we still recommend loading Facebook’s standard pixel, and if you do this through Segment, Facebook will deduplicate when it receives the same events from both the pixel vs. CAPI. Chrome’s latest cookie deprecation will have huge implications, and the CAPI will be more reliable and important for tracking than ever! Network issues like ad blockers or tracking restrictions do not affect server-side conversions, because they send user data to your website first, before being transferred to the tracking platform. 

  2. New Additional Events: There may be key events that you only track server-side, or additional events that happen somewhere else lower in the funnel (e.g., In-app, CRM, Support, Post-Purchase, etc.). With Segment you can simply stream these server-side events over to Facebook and optimize your ads not just based on website behavior, but any time during a customer lifecycle.

Segment's integration with Facebook CAPI provides a unified, efficient, and reliable method for businesses to collect and stream customer data to their entire tech stack, including analytics, data warehouses, CRM, marketing tools, and the Conversions API. This eliminates the need for additional engineering effort to build one-off integrations.


Rules and regulations around customer privacy are constantly evolving and  Segment continues to remain committed to engaging advertisers while remaining compliant.

For a step-by-step guide on how to send Segment collected first-party-data to Facebook for retargeting, read this recipe.

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