Why you need both? And Why They’re Different
The modern marketing world has evolved over the past decade, with tracking setups becoming a central topic of discussion. This often lands you on the topic of client-side and server-side containers.
A container sounds technical but the underlying concept is relatively straightforward. Understanding the difference is essential if you want accurate data, better privacy control and an analytics setup prepared for future data legislative restrictions.
What is a container?
When discussed in the context of tracking and analytics, a container is a central place where your tracking lives.
It contains things like:
- Tags (what data to send)
- Triggers (when to send it)
- Variables (extra information about the user or event)
Instead of hardcoding tracking scripts across your site, a container lets you manage everything in one place.
Think of it as the configuration hub which controls your data collection.
Understanding Client-Side vs Server-Side
Before we get too into the weeds, it’s important to understand the terms themselves.
- Client side refers to the code that runs in the user’s browser, on their device
- Server side refers to the code which runs on the server you control.
A common misconception is that client-side means “what the user sees” and server-side means “what happens when they click.”
The real distinction is where the code is executed:
- If it runs in the browser → client-side
- If it runs on a server → server-side
What Is a Client-Side Container?
A client-side container runs in the user’s browser.
This means when someone visits your website:
- Their browser loads your container (e.g. via Google Tag Manager)
- The container executes tracking scripts using JavaScript
In the context of our data setups, the client-side container primarily acts as a data collection layer, whereas the server-side container handles processing and distribution.
What Is a Server-Side Container?
A server-side container runs on a server.
The flow changes:
- The user visits your website
- The browser sends data to your server (your endpoint)
- Your server-side container processes that data
- The server hashes, cleans, and unifies it then forwards it to analytics and advertising platforms
Instead of multiple third-party requests leaving the browser, everything passes through your own server first.
In this setup, data is first received from your website via the client-side container, then processed on the server before being forwarded to analytics and advertising platforms.
Because all data passes through this layer, you have much greater control over how it is handled. This allows you to filter out bots and unwanted traffic, clean and validate incoming data, and unify it into a consistent structure before sending it on.
In effect, the server-side container acts as a central processing layer, ensuring that the data you share with third-party platforms is more accurate, consistent, and intentional.
Why This Shift Is Happening
Modern browsers and privacy regulations have changed how tracking works.
Client-side tracking is increasingly affected by:
- Ad blockers
- Browser privacy restrictions
- Limited cookie lifespans
As a result, many businesses are moving toward server-side containers to maintain reliable data collection and greater control.
Why Use Both Client-Side and Server-Side Containers?
In many modern tracking startups, businesses use both client-side and server-side containers. Each plays a different role in how data is collected and processed.
The client-side container is where tracking begins. Because user interactions happen in the browser, it’s responsible for capturing events like page views, clicks, and form submissions. Without this layer, you wouldn’t be able to detect what users are doing on your site in real time.
That data is then passed to the server-side container, which acts as a controlled processing layer. This allows you to filter out bots and unwanted traffic, clean and validate incoming data, and unify it into a consistent structure before sending it on. It also enables you to treat data as first-party, since it is collected and processed through your own domain before being shared externally.
This combined approach allows you to:
- Capture user behaviour at the source (client-side)
- Maintain control over how data is processed and shared (server-side)
In setups using platforms like Stape, the client and server containers work together seamlessly creating a more structured and reliable data flow without losing visibility into user activity.
Why is this First Party?
This approach also supports a first-party data strategy because the data is collected and processed through your own domain and infrastructure before being hashed and shared. Instead of the browser sending information directly to external vendors, it communicates with your server endpoint, which sits under your control. As a result, the data is less likely to be restricted or blocked, and you retain greater ownership over what is collected and how it is used.
Key Takeaways
A container is the foundation of your tracking setup; it determines how your data is collected and distributed. Client-side containers run in the browser, and other marketing agencies send data directly from these platforms. Server-side containers run on your server and act as a controlled layer between your site and third parties.
As tracking becomes more complex and privacy-focused, understanding this distinction is vital, it’s essential for making informed decisions about your data strategy.
We simplify and maintain this process over on our software, Lupe.
