Conversions API: How marketers can improve ad results and adapt to privacy changes

With third-party cookies declining due to privacy rules and ad blockers, marketers face the challenge of maintaining effective targeting and performance. 

Enter Conversions APIs (CAPIs). They let you upload your first-party data straight to ad platforms, ensuring accurate targeting and on-platform attribution. With improved signal quality, ad platforms can optimize their algorithms, leading to better results and a higher return on investment for advertisers.  

Unsure about whether Conversion APIs are relevant for you and how exactly they work? We’re here to explain it all.

Navigate this post:

• What is Conversions API?
• Why are Conversions APIs the future of advertising? 
• What platforms offer CAPIs? 
• Conversions API integration options  
• Best practices for Conversion API integrations  

What is Conversions API?

Conversions API is a secure channel that lets advertisers send conversion data to publishers like Meta or Google, provided that they have all the necessary rights and permissions. The CAPI creates a direct, reliable link between your marketing data—whether from your server, website, app, or CRM—and publishers. 

You can track a range of events using Conversions API, including:

• Website events: For example, when a user adds an item to their cart in an e-commerce store, 
• App events: When a user completes a level in a mobile game.
• Offline conversions: When a customer purchases a product in-store. 
• Messaging events: When a user sends an inquiry about a product via Facebook Messenger or Instagram Direct.
• CRM events: When a sales rep logs a phone call with a prospect in a CRM.

Using CAPIs allows you to personalize, optimize, and measure your ads more effectively. CAPIs prevent signal loss—the main issue with third-party cookies—ensuring your ads reach the right audience, all while respecting peoples’ privacy. 

How is Conversions API different from cookies?  

Conventionally, digital marketing has relied on data collected through cookies. When you visit a website, various pixels track your activity as you navigate through the home page, product pages, and checkout pages. These pixels capture data and send it through the browser to advertising channels.

This data transfer is an automatic process that captures parameters like IP address, country, and click ID. So if a user browsed the Zalando shoe section but didn’t complete a purchase, Zalando could use those parameters to re-target that user with ads. 

Traditional web pixels like the Meta Pixel (previously Facebook Pixel) rely on the user’s browser to send data. However, since users can opt out of sharing their data, this information can be blocked. So, if the shoe shopper opted out of data collection, Zalando wouldn’t be able to identify and re-engage with them later. 

In contrast, the Conversions API sends data directly from your server to publishers, so browser limitations and cookie restrictions won’t affect it. 

Why are Conversions APIs the future of advertising? 

The shift away from third-party cookies is an opportunity for marketers to get ahead with CAPIs. More than a cookiless tracking alternative, CAPIs offer better data accuracy, stronger privacy compliance, and a direct link between your tools and platforms. Embracing it now sets your business up for privacy-compliant and effective marketing.

Optimize your ad spending 

CAPIs provide a complete and accurate view of customer interactions, leading to better decision-making and more efficient spending. Meta studies show that using CAPIs can deliver:

• Up to 19% additionally attributed events
• Up to 13% cost per result improvement
• A 44% increase in the rate of converting a lead to a quality lead

Over time, this 13% cost reduction can make a big difference for any business running marketing campaigns.

Provide better conversion tracking

As third-party cookies phase out, CAPIs allow you to collect data directly from your server. Unlike traditional tracking, which relies on the user’s browser and can be hindered by ad blockers, server-side tracking captures data on a dedicated server, delivering much higher-quality data.

After capturing data on your server, you can adjust and send it to your analytics and marketing tools. This keeps you in control of the data, reduces reliance on third parties, and allows you to manage data protection levels—without changing your existing tools.

Since CAPIs track conversions from users who reject traditional tracking methods, this approach closes conversion data gaps and leads to more accurate reporting. 

Improve audience targeting

By collecting data directly from your server, CAPIs give you a clearer understanding of your audience, allowing for more precise targeting. For example, you can avoid showing ads to people who’ve already purchased your product. 

Ad platforms rely on this user data to improve their targeting, and with CAPIs providing more accurate data, they can target ads better, leading to a higher return on investment.

Provide accurate marketing attribution and measurement

Due to their reliability, CAPIs allow you to see more conversions than you would be able to with web-based pixels. They give you a more precise and comprehensive view of conversion events, improving the measurement and optimization of your marketing efforts. 

CAPIs reduce data loss, giving you more reliable attribution. This helps you pinpoint which campaigns and touchpoints are driving conversions, even with strict privacy measures in place.

What marketing platforms offer CAPIs? 

Nearly all advertising platforms have developed their own Conversions API to ensure marketing data can be shared effectively for advertising purposes.

Facebook Conversions API  

The Facebook Conversions API (Facebook CAPI) creates a direct connection between your marketing technology and Facebook, giving you the data you need to better optimize your ads. 

Meta recommends setting up Conversions API in addition to the Facebook Pixel since the Conversions API captures more data than the Pixel. As long as third-party cookies are still around, you can keep using the Pixel. 

Meta also recommends a redundant event setup when using both the Pixe and CAPI. For a full installation guide, check out Facebook’s help center and developer documentation. 

LinkedIn’s Conversions API

With LinkedIn’s Conversions API, you can connect both your online and offline data to LinkedIn. This lets you see how your campaigns influenced actions on your website, phone sales, or leads collected in person at events.

Learn how to set it up on LinkedIn’s help center. 

TikTok’s Events API

You can set up TikTok’s Events API through your in-house technical team or a third-party partner. Like Meta, TikTok recommends using both Events API and TikTok’s Pixel together with Event Deduplication to maximize your ad performance. 

Get all the info you need about implementing TikTok’s Events API and Pixel on TikTok’s help center. 

Pinterest’s Conversions API

Pinterest’s Conversions API builds a bridge between your website, app, and offline sales directly to Pinterest’s analytics engine. Pinterest allows you to send conversion data via third-party partner integrations or direct integration. 

Visit Pinterest’s help center guide for an onboarding overview, and take a look at their free Conversions API course for best practices. 

X (Twitter) Conversions API

X’s Conversions API lets you track the actions people take after interacting with one of your ads. It can work with or without the X Pixel. X also recommends deduplicating events between the Pixel and the Conversions API.

You can read X’s step-by-step Conversions API setup guide for more details. 

Google Ads’ offline conversion API 

Google Ads offers an API for uploading offline click conversions, allowing you to track how ads lead to offline sales, such as over the phone or through a sales rep.

Learn more about Google’s offline conversion API in their help center. 

Conversions API integration options  

While each platform outlines its own CAPI set-up process, there are essentially three different ways to set up Conversions APIs. 

Native CAPI provided by the platforms

Native CAPI integrations offer an easy way to connect data with your marketing platforms. For example, you can use Shopify’s built-in CAPI integrations to send data to Meta and other advertising platforms. 

Pros: This feature is typically offered at no extra cost by native platforms.

Cons: You need to manage separate CAPI streams across different platforms. For example, in this case, you can only get data from Shopify and Meta. But what if you want to push it to a different platform or want to enrich the data first? 

Do-it-yourself CAPI

This is when you have engineering teams build data pipelines to get data into a data warehouse and then reverse ETL it to a conversion API.

Pros: You can have all your CAPI streams in one place, so it’s easier to manage. 

You can also completely customize the system to your needs. Depending on your tech stack, use cases, and data silos, a partner might not meet all your needs. In such cases, building a tailored solution to address your specific requirements might be the better choice. 

Cons: You need both a data warehouse and engineering resources to execute and maintain the system, even if you buy a platform for reverse ETL. Building CAPI yourself is a big effort that can take weeks or even months. 

All-in-one CAPI 

An all-in-one CAPI solution not only brings the data in, but also streams the data to CAPIs without the need for technical expertise.

Pros: You can again centralize all your CAPI streams, making them easier to manage. A big plus here is that you don’t need any technical resources.

4 best practices for Conversions API integrations  

The best marketing tools are only as good as what you put in. How can you improve the effectiveness of your Conversions API?

1. Maximize your event coverage

Event coverage with the Conversions API means sending a comprehensive set of relevant events (or customer interactions) to advertising channels. To get the most value from Conversions APIs, it’s not about sending more data—it’s about sending the right data for your business. 

Map your customer journey and identify the most important events for your business—whether that’s page views, sign-ups, or purchases. Be sure to share the same number of events (or more) using the Conversions API as you do with web-based pixels. 

2. Automate the process  

To keep your data fresh, automate the process of sending events to advertising platforms. Automation ensures that your data flows consistently, helping platforms perform better by receiving timely updates.

By sharing events regularly and without delay, your ad delivery system can more accurately determine how likely someone is to take your desired action after seeing an ad. This continuous flow of data keeps your campaigns optimized and responsive.

3. Remove duplicated events 

Platforms like Meta and TikTok recommend adding deduplication keys with each event to avoid counting events twice and ensure accurate data. Fortunately, most conversion data already comes with a unique identifier for each event, making it simple to implement deduplication. 

Regularly check that your events are being deduplicated, and aim for a high deduplication rate to keep your data precise and reliable. 

4. Run tests 

Regularly test and optimize your advertising strategies. For example, Meta recommends a couple of testing options:

• Conversion lift: Measure the incremental performance impact of using server events.
• Split testing: Determine which conversion marketing strategy delivers the best and most efficient outcomes to optimize your performance. 

Towards a first-party data strategy 

As third-party cookies continue declining, CAPI is a great alternative that allows accurate targeting and reliable attribution. If you’re looking into investing in CAPI (or other cookiless tracking methods), you need to get serious about your first-party data strategy. It’ll allow you to collect accurate data about your audience, improve targeting performance, and fuel advanced marketing measurement models such as marketing mix modeling.