Privacy & Tech

What is the difference between client-side and server-side tracking?

The main difference is where tracking data is collected, processed and routed. Client-side tracking runs in the visitor’s browser, while server-side tracking processes event data on a server before sending selected information to other services.

Aspect	Client-side tracking	Server-side tracking
Processing location	The visitor’s browser.	A server or server container.
Typical data route	The browser sends events directly to measurement or advertising providers.	Events are sent to a server before being forwarded to selected providers.
Data controls	Applied through browser-side code and tag settings.	Server-side rules can filter, modify or enrich information before forwarding.
Browser involvement	Browser code typically collects and sends events.	The browser may still collect and send the initial event.
Privacy obligations	Depend on the data collected, purpose and applicable law.	The same assessment applies to the complete data flow.

Many implementations combine both approaches. For example, a browser can collect a purchase event and send it to a server, where the server determines which fields are forwarded to each provider. Google’s documentation on server-side transformations describes how these controls can be applied.

Server-side tracking does not necessarily replace client-side tracking. It changes where some processing and data routing take place. It can provide greater control over the information sent to third parties, but those controls must be configured correctly.

The architecture itself does not determine whether tracking is compliant or requires consent. That depends on the information collected, how it is used, who receives it and the applicable law.