What to know about server-side tracking + conversion APIs

March 25, 2024

Tom Segar
Adapting to the post-third-party-cookie era? Discover how server-side tracking & conversion APIs are reshaping digital marketing amid the third-party cookie phase-out.

What to know about server-side tracking + conversion APIs

Read here to get a background on third-party cookie depreciation.

MacBook Pro on white surface

After years of delays, Google has started implementing its plan to deprecate third-party cookies. While Safari and Firefox have been blocking cookies for years, Google disabled third-party cookies for 1% of Chrome users in early January 2024 and is continuing to vocalize its plans to phase out cookies for 100% of Chrome users in 2024. Although some of Google’s recent Privacy Sandbox posts could be interpreted as evidence that the timeline may be extended, the time is now for marketers to prepare for a cookieless world.

Among other strategies, leveraging first-party data and platform conversion APIs will allow marketers to continue collecting and using site behavior and conversions for marketing when third-party cookies are no longer reliable. Adding this tactic to your overall cookie deprecation plan will help prepare for the future.

The first step to deciding if this strategy is right for you is understanding how server-side tracking is different from traditional browser-side cookies, and what conversion APIs do. Fair warning: the content that follows is a bit technical. Have questions? The CM team is here to help. 

Understanding pixels versus server-side tracking and conversion APIs

Most digital marketers are familiar with cookies and pixels as they have been around since the early days of digital advertising. Although server-side tracking is well-established, platform-specific conversion APIs have been developed more recently and some platforms are starting to push their users to adopt the tool. Some platforms have even encouraged the use of conversion APIs with financial incentives. To clear up any confusion, let’s define cookie data storage and a traditional platform pixel and then compare it to server-side data storage and conversion APIs (Application Programming Interface). 

Cookies and pixels

In a cookie and pixel scenario, a visitor’s behavior is collected via a cookie and stored on the visitor’s browser. This is commonly referred to as “client-side” or “browser-side” because the visitor is the client using a web browser. The data are then sent from the visitor’s browser to an advertising platform via a third-party pixel placed on the site.

Server-side tracking and conversion APIs

With server-side tracking, a visitor’s behavior is collected and sent to a server managed by the brand, which is why it is referred to as “server-side.” When properly configured, the provisioned server is recognized as a first-party data platform. Conversion APIs are used to send the first-party data from the server to the advertising platform via an API, bypassing your visitor’s browser. 

Platform APIs

As of March 2024, Facebook, X (Twitter), TikTok, LinkedIn, and Pinterest offer their own dedicated conversion API solutions. These conversion APIs facilitate the direct transfer of first-party data from your server to the advertising platform, contributing to increased security and reliability in the data transfer while circumventing the dependence on third-party cookies.

Marketers will need to research each platform’s API configuration as they differ. It will be critically important to understand any required website code changes and what types of conversions can be tracked.

A potential complication when setting up conversion APIs is that sites can use both third-party platform pixels and the platform’s conversion API. In fact, some platforms like Facebook currently prefer brands to have both. Although this provides data redundancy (which typically results in increased coverage), it also requires deduplication processes to be set up.

Opportunities and challenges of server-side tracking and conversion APIs

The opportunities presented by server-side tracking and conversion APIs outweigh the challenges, but there are some important technical aspects that should be considered.


  • Marketers own and manage the first-party data on their secure server
  • Data are not limited by third-party cookie deprecation, ad-blockers, or browser settings as the data are stored on a server, not on the visitor’s browser. Marketers have observed 10%–30% higher pageview events and up to 100% higher purchase events using server tagging versus browser tagging
  • Without third-party cookies, server-side data paired with conversion APIs will provide a reliable source of site event and conversion data
  • Moving tagging server-side makes for fewer pixels and scripts loading on your website. This can lead to increased site speed (which is associated with positive SEO impacts) as well as an improved user experience for your visitors. Keep in mind that some advertising platforms like Facebook recommend a dual-tagging set-up on both the server-side and browser-side in a web container, so make sure to weigh these options and what is best for your overall business


  • If you don’t have an existing server available to receive data, there may be incremental costs incurred for server hosting (e.g., via Google Cloud Platform)
  • Some technical knowledge will be required for server set up. Your website’s DNS (Domain Name System) needs to be modified to recognize the server as a first-party data platform to ensure data can be passed without incident
  • While one server might be used for data storage for multiple ad platforms, each ad platform will require its own conversion API
  • If using a platform’s conversion API and traditional platform pixels, event information may be sent to the platform twice, which could potentially lead to double-counting. Some ad platforms (such as Facebook and LinkedIn) offer deduplication support, but it’s important to understand if this could be an issue at the platform level

What marketers need to know

As third-party cookie deprecation continues to progress, sooner is better for deciding if server-side tracking and conversion APIs should be part of your plan to wean off of third-party cookie reliance. Server-side tracking and conversion APIs are not the single solution for third-party cookie deprecation, but the client-managed server will allow marketers to control first-party data in a secure location while platform conversion APIs provide a reliable way to send these valuable data to your advertising platforms. However, you should understand that the process will most likely require some technical resources and help from your website developers to bring it to life.