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Ultimate guide to Conversions API implementation with Google Tag Manager

En el ecosistema de la publicidad online, la medición es crucial para lograr un retorno positivo de la inversión. Tradicionalmente, la medición se basaba en las cookies de terceros almacenadas en los navegadores, que plataformas como Facebook o TikTok utilizaban para recopilar datos. Sin embargo, con el anuncio por parte de Google del cese de las cookies de terceros a partir de 2024, los anunciantes se enfrentaron a una caída potencial del 300% en la eficacia de la publicidad online. La única solución se presentaba como la medición de las campañas online mediante el envío de conversiones a través de API.



In the evolving ecosystem of online marketing, the ability to measure and analyze user interactions with your website, advertisements, and digital assets is paramount. This process, known as online measurement, serves as the compass guiding businesses to navigate the dynamic realm of digital marketing successfully.

Online measurement plays a pivotal role in:

  • Evaluating the performance of advertising campaigns.

  • Understanding the audience and their preferences.

  • Identifying areas for improvement on your website.

  • Making informed decisions to optimize marketing strategies.

For a considerable duration, the tracking of digital marketing campaign events has relied heavily on third-party cookies deployed through pixels on websites. A pixel, a code loaded into your browser, serves as the silent observer, meticulously measuring user behavior.

At the heart of this measurement lies the pixel – a small but powerful code that captures and interprets user actions. Widely employed by various platforms, pixels are instrumental in attributing conversions, providing invaluable insights into the effectiveness of marketing efforts.

Integral to this tracking mechanism are cookies, those tiny data fragments nestled within a user's browser during their website visit. These cookies, akin to a digital trail, meticulously record online activities, preferences, interactions, and notable behaviors—such as completed purchases.

As we delve deeper into the intricacies of online measurement, it becomes evident that the traditional reliance on third-party cookies and pixels is undergoing transformation. 


Understanding Conversions API

Major advertising platforms, including industry giants like Meta, TikTok, Google, Pinterest, Snapchat, and X (Twitter), have long relied on pixels for conversion attribution. Yet, the reliability of these pixels is under threat from ad blockers and connectivity issues. Privacy policies have undergone substantial changes since 2018, raising concerns about user tracking:

  • 2018: The General Data Protection Regulation (GDPR) introduced initial restrictions on cookie transmission.

  • 2019: Operating system providers announced policies allowing users to opt-out of tracking.

  • 2020: The European Data Protection Board (EDPB) established new guidelines for cookie treatment and consent banners.

  • 2021: A new privacy framework was introduced to restrict data transmission in iOS 14.

  • 2023-2024: The "Privacy Sandbox" was announced, and Google Chrome is expected to stop using third-party cookies by the end of 2024.

Most pixels depend on third-party cookies to track user activity. As you may have heard, by early 2024, approximately 85% of browsers, including Google Chrome, will block these cookies by default, endangering the ability to identify users through pixels.




The potential consequences of ineffective pixels are significant, including the inability to track, attribute conversions, optimize campaigns, retarget, and create custom audiences on websites. A 300% average increase in cost per action (CPA) between conversion campaigns and link clicks is projected.

Looking ahead, as browsers phase out third-party cookies, sending events through the Conversions API via server-side implementation will become the only viable method to maintain traceability of user activity on our website.

What is Conversions API

Conversions API (CAPI) is a data transmission method used in online advertising to send user interaction and conversion data from a website or app to advertising platforms' servers. It operates on the server side, meaning that data is sent directly from the web server or application server to the advertising platform's server, bypassing the need for client-side tracking via browser-based pixels.

Here are key aspects of Conversions API:

  1. Conversions API works by transmitting data directly from the server where your website or application is hosted to the servers of advertising platforms.

  2. It provides a more reliable and accurate way to track user interactions and conversions, ensuring that the data received by advertising platforms is complete and trustworthy.

  3. As privacy concerns grow and browsers implement changes like blocking third-party cookies, server-side methods like CAPI become increasingly important for maintaining accurate tracking while respecting user privacy.

  4. CAPI allows for more accurate cross-device tracking since data is sent directly from the server, reducing the reliance on cookies stored on individual devices. 

  5. Conversions API plays a crucial role in attribution modeling by providing a comprehensive view of user interactions throughout the customer journey. 

  6. With changes in privacy regulations and browser policies, Conversions API is considered a more future-proof solution compared to traditional tracking methods reliant on cookies and pixels.

  7. Advertisers can integrate Conversions API into their data transmission strategy to ensure seamless communication with these platforms.


Moving from Third-Party to First-Party data collection

In the wake of evolving privacy concerns and a shifting digital landscape, the transition from third-party to first-party data collection has become a strategic imperative for businesses aiming to stay ahead in the online marketing game. This paradigm shift not only aligns with emerging privacy regulations but also presents a unique opportunity for more reliable and direct insights into user behavior.

Historically, third-party cookies and pixels have been the workhorses of data collection, providing marketers with a wealth of information about user interactions. However, with privacy becoming a central focus and web browsers increasingly restricting the use of third-party cookies, marketers face the challenge of adapting their measurement strategies.

First-party data, on the other hand, represents a fundamental shift in how businesses collect and utilize customer information. Unlike third-party data, which relies on external sources and cookies, first-party data is directly obtained from your audience through their interactions with your website, apps, and other digital touchpoints.

Advantages of First-Party data:

  • Trust and transparency: Building trust with your audience is crucial. First-party data collection fosters transparency by explicitly informing users about the data being collected and how it will be used.

  • Data accuracy: Directly sourced from your audience, first-party data tends to be more accurate and reliable. This accuracy is paramount in making informed decisions based on authentic user behaviors.

  • User control: Empowering users with control over their data enhances their experience. With first-party data, users can manage their preferences and opt-out if they choose, reinforcing a sense of control over their online interactions.

Conversions API, when integrated with Google Tag Manager, seamlessly facilitates the shift towards first-party data collection. By directly transmitting data to your server, Conversions API allows you to capture and utilize user interactions in a privacy-friendly manner.

This integration not only ensures compliance with privacy regulations but also positions your business to thrive in an environment where users value privacy and transparency.


What are Conversions API main benefits?

The adoption of Conversions API brings about a paradigm shift in the way advertisers track and measure conversions. The increased visibility into the marketing funnel and the reliability of the tracking signal position Conversions API as a vital tool for advertisers looking to navigate the evolving landscape of online advertising with accuracy and resilience.

Increased funnel visibility

Implementing Conversions API (CAPI) provides advertisers with a heightened level of visibility into the entire marketing funnel. Unlike traditional pixel-based tracking, which may encounter limitations due to privacy changes and ad-blockers, Conversions API operates on the server side, allowing for a more comprehensive understanding of user interactions at every stage of the customer journey.

  • Holistic tracking: By capturing user activities beyond the limitations of cookies and pixels, Conversions API enables advertisers to monitor user engagement, from initial touchpoints to final conversions. This holistic tracking ensures a more accurate representation of the customer journey.

  • Attribution across channels: CAPI facilitates cross-channel attribution by consolidating data from various touchpoints. This comprehensive view helps marketers understand the interplay between different marketing channels, allowing for more informed decision-making and optimized campaigns.

  • Insights into customer behavior: The server-side approach of Conversions API enables advertisers to gain deeper insights into customer behavior, preferences, and interactions. This granular understanding contributes to more targeted and effective marketing strategies.


Reliability and resilience of the signal

Conversions API offers a robust and resilient signal for tracking and measuring user interactions. Unlike pixel-based tracking, which may be affected by ad-blockers, browser changes, or privacy regulations, the server-side nature of CAPI ensures a more stable and consistent flow of data.

  • Adaptable to privacy changes: As privacy regulations evolve, Conversions API remains adaptable. The server-side implementation allows advertisers to navigate privacy challenges more effectively, ensuring continuous access to valuable data for measurement and optimization.

  • Reduced dependency on cookies: With the impending phasing out of third-party cookies, Conversions API becomes an essential solution. By relying less on cookies and more on server-side data transmission, CAPI provides a more reliable and future-proof method of tracking user activity.

  • Minimized impact of ad-blockers: Ad-blockers often disrupt traditional pixel tracking methods, leading to incomplete data and inaccurate measurement. Conversions API minimizes the impact of ad-blockers by operating at the server level, preserving the integrity of the tracking signal.

  • Consistent data accuracy: The server-side approach ensures the consistent and accurate transmission of data to advertising platforms. This reliability is crucial for precise measurement, effective campaign optimization, and building a trustworthy foundation for data-driven decision-making.

It's worth noting that the adoption of the Conversions API has been limited due to its complexity and costs, requiring developer tools, server setup and maintenance, and programming skills. Despite its importance for marketers, this complexity has hindered mid-level advertisers from embracing this technology.


Introduciendo Adsmurai One Tag

Adsmurai's response to these challenges is "Adsmurai One Tag" (previously known as "Serverless Tracking"). This solution provides a complete implementation of pixels and the Conversions API through a subscription model, meticulously crafted to meet the needs of brands. One Tag is a serverless, code-free solution available through three subscription plans, each tailored to accommodate varying event volumes. Compatible with platforms such as Meta, Pinterest, TikTok, and Google, One Tag de Adsmurai stands out as a user-friendly alternative.



Key Features of Adsmurai One Tag:

  1. Complete Pixel and Conversions API Implementation
  2. Flexibility in choosing a plan that aligns with the volume of events, providing scalability for brands of various sizes.
  3. Advertisers can implement tracking without the requirement for extensive coding skills, reducing barriers to entry.
  4. One Tag de Adsmurai is compatible with major advertising platforms, including Meta, Pinterest, TikTok, Snapchat and Google. 
  5. The "Tracking Health" feature enables easy monitoring of the status and health of implemented pixels and events, providing transparency and control over the tracking process.
  6. Advertisers can set up their subdomain to avoid ad blockers and treat the data as 1st party.


Until now, the conventional approach involved inserting the platform pixel into the user's browser through Google Tag Manager. However, with Adsmurai's One Tag, a new method emerges. User activity on a website is not only transmitted through the pixel, as done previously, but also via the Conversions API. This process utilizes Google Tag Manager hosted on the server side in a Google Cloud server. It receives user activity, formats it correctly, and sends it to the platform, offering a more resilient and future-proof solution.


Setting up Google Tag Manager

As you may know, Google Tag Manager is a powerful tool that simplifies the process of managing and deploying various tags on your website without the need for extensive coding. Tags include snippets of code or tracking pixels from analytics tools, advertising platforms, and more.


Quick set up for Google Tag Manager

  1. Account creation: Start by creating a Google Tag Manager account by visiting the GTM website and signing in with your Google account.

  2. Container setup: After creating an account, set up a new container within GTM. A container is a dedicated space for managing tags on a specific website.

  3. GTM container code: Once the container is set up, GTM provides a unique container code. Copy this code.

  4. Inserting code on your website: Paste the GTM container code into the header section of your website. This enables GTM to start managing tags for your site.

Setting up Google Tag Manager provides a centralized and streamlined approach to managing tags, including the seamless integration of Conversions API for efficient tracking and data transmission.

How to set up Conversions API with One Tag

Let’s learn how to keep traceability of user's activity on your website in just a few clicks:


Get your Pixel ID and access token in the platforms Business Manager:






Go to the Meta Business Manager.

Go to the

TikTok Events Manager.

Go to the Pinterest Events Manager.

Go to the Snapchat Events Manager.

Select the "Web Events" section.

Copy and save your Pixel ID.

Copy and save your Pixel ID.

Copy and save your Pixel ID.

Copy and save your Pixel ID.

Navigate to the “Settings” section.

Navigate to the "Settings" section.

Navigate to the "Settings" section.

Navigate to the "Settings" section.

Click on “Generate access token”.

Click on "Generate access token".

Click on "Generate access token".

Click on "Generate access token".

Copy and save this token

Copy and save this token.

Copy and save this token.

Copy and save this token.

Add a new pixel in Adsmurai One Tag and generate my API key

  • Access your user area in Adsmurai One Tag.

  • Click on the "+" symbol to add a new pixel.

  • Paste both the Pixel ID and access token obtained from Meta.

  • Generate your Adsmurai One Tag API key.

  • Copy and save this generated API key.


Integrate the API key in Google Tag Manager

  • Go to your Google Tag Manager container.
  • Open the One Tag label.
  • Paste the API key generated previously in Adsmurai One Tag.
  • Configure the label with the provided information.
  • Save the changes made.

Best practices to implement Conversions API with One Tag

By following these best practices and employing effective troubleshooting strategies, you can ensure a smooth and reliable Conversions API setup with Adsmurai One Tag, while maintaining traceability of user activity on your website.


Organized Pixel ID and Access Token management

Maintain a well-organized record of Pixel IDs and access tokens on Google Tag Manager by storing them and using .


Set up the required events for Dynamic Ads

Follow the guidelines to set up the required events and parameters needed to run Dynamics Ads. For example, for an e-commerce, the minimum events for Meta would be:

  • ViewContent
  • AddToCart
  • Purchase


Value and currency values are mandatory

When sending events related to purchases, make sure to send the value and the currency the value is in. Otherwise the channel will reject the server event.


Hash all user data

Use the SHA256 encoding to send user details like email or phone number, which is a requirement by all major providers. One Tag has a checkbox to automatically do it.


Use the same triggers

It is recommended to use the same triggers for similar actions in order to avoid channel discrepancies. One Tag is a good way to do so, as it allows to unify all events into one.




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