How conversion APIs improve campaign performance

It should come as no surprise that when the goal is performance marketing, data is king. Without data, you cannot optimise your campaigns. Hence, you can’t maximise your ROI. Sounds obvious, doesn’t it?

But what can we do when third-party cookies are on the brink of demise, iOS 14 privacy changes are in full swing, and we are unable to collect the data that we need to optimise our campaigns? Enter: Conversion APIs.

What are conversion APIs?

A conversion API, also known as a server-side API, is a tool that allows you to send data from your server to third-party advertising platforms. This means you can send events from your CRM straight into Meta, TikTok, or other advertising platforms.

Because conversion APIs are not limited by tracking or cookies, they are flexible and reliable. The data being shared is coming straight from your own server rather than relying on browser-based tracking methods, like a web pixel, that are becoming increasingly ineffective due to privacy regulations and user preferences.

What is the difference between conversion APIs and pixels?

A web pixel is a code snippet that sits on your website and collects data to send back to third-party advertising platforms. Because it sits on your website, it is impacted by users not accepting cookies, not wanting to be tracked, and all the other privacy regulations in place. This means that a pixel has become less effective in fully communicating the value of your campaigns. It also means that less data is being shared with your chosen advertising platform, so the campaigns are not being optimised to the best of their ability.

Conversion APIs, on the other hand, bypass all these hurdles and send through all your data directly to advertising platforms. Since they are not reliant on users accepting cookies, the data stored in your own server provides a complete picture that can be passed back to ensure your campaigns are performing at their best.

What can you track with conversion APIs?

One of the biggest advantages of conversion APIs is the breadth of data they can capture. Unlike browser-based tracking, which is limited to what happens on the website, conversion APIs allow you to track:

• Website Events: Just like pixels, conversion APIs can track page views, button clicks, add-to-cart events, and purchases, but with higher reliability.
• Offline Conversions: If a sale or lead conversion happens offline, such as in a store, via a phone call, or through an email follow-up, conversion API ensures that data is still captured and linked back to the campaign.
• Cross-Device Behaviour: With users switching between devices, conversion APIs help track interactions across mobile, tablet, and desktop more effectively than browser cookies.
• First-Party Data: conversion APIs allow advertisers to send customer data securely, ensuring a higher match rate for better targeting and attribution.

How does conversion API improve campaign performance?

Now that we understand how conversion APIs work, do they actually improve campaign performance? The short answer is ‘yes’. The long answer is ‘hell yes’.

But how, you ask? There are several ways your campaign performance improves through the implementation of conversion API:

1. Smarter campaign optimisation

Because conversion APIs pass back all the data in the server, including from users who did not accept cookies, the additional data means your bidding strategies work more efficiently. It also means that you can have improved audience targeting because you have a complete view of the data and can improve your targeting accordingly.

This ultimately leads to more efficient ad spend, as platforms like Meta, Google, and TikTok use the additional data to refine audience segmentation, improve lookalike audience accuracy, and enhance retargeting efforts.

2. Ability to track offline conversion data

One of the key things that conversion APIs can do but a pixel can’t is pass back conversions that are not happening on the website. If you’re a lead generation business where your sale actually happens much later after generating a lead, your browser-based pixel will never be able to capture that data.

Similarly, if your business sees most conversions happen offline, like in a physical store or over the phone, your campaigns will only track online interactions, missing crucial touchpoints in the funnel. Conversion API helps you pass back this data so your campaigns can optimise towards metrics that impact your bottom line.

3. More accurate reporting

One of the biggest downsides of cookie depreciation was not being able to report accurately on campaign performance. When the data being passed into the platform was incomplete, so was the reporting. But with conversions API, you get a full picture of your campaign performance and can better prove the value it is generating to your clients or stakeholders.

With accurate data, you can measure ROAS (Return on Ad Spend) more precisely and make data-driven decisions to scale successful campaigns and cut ineffective ones.

4. Improved understanding of the customer journey

Since conversions  API captures behavioural data and enables cross-device tracking, it provides an improved understanding of user behaviour. This means you can:

• Attribute conversions more effectively.
• Identify high-intent users earlier in the journey.
• Understand which touchpoints are driving the most engagement and revenue.

Rather than relying on fragmented data from different devices and browsers, conversion APIs create a more cohesive view of how users interact with your brand before making a purchase or completing a lead form.

Are there any downsides to using conversion API?

As with anything, there are some downsides to using conversion APIs. However, the benefits far outweigh them.

1. Technical knowledge is required

Implementing conversion APIs is not as simple as adding a tag to your GTM container. It requires development resources and a deeper understanding of server-to-server integration.

2. Time-consuming setup

Unlike a pixel, which can be implemented in minutes, setting up conversion API can take more time, especially since you need to configure it separately for each advertising platform.

3. Ongoing maintenance is needed

Pixels are more of a one-time set up, but conversion APIs require ongoing monitoring to ensure data accuracy and proper integration with your advertising platforms.

Which advertising platforms offer a conversion API?

Multiple platforms have introduced their own version of a conversion API to help advertisers maintain campaign performance in a privacy-first world. Some of the major platforms that support conversion API include:

• Meta Conversion API
• Google Enhanced Conversions API
• LinkedIn Conversion API
• TikTok Events API

Should you implement a conversion API?

The short answer: Yes. If you’re running performance-driven campaigns and want to ensure you’re getting the most out of your ad spend, implementing conversion APIs is one of the best ways to future-proof your tracking and optimisation efforts.

As the advertising landscape continues to shift towards more privacy-focused solutions, relying solely on pixels will put your campaigns at a disadvantage. By integrating conversion API, you gain access to richer data, smarter campaign optimisation, and ultimately, better results.

So, if you haven’t already made the move, now is the time to explore conversion APIs. Your campaigns will thank you for it. Speak to our Data and Insights team to learn more.