Lesson 2 of 18
The Key Components
A server containerserver containerA GTM container that runs on a server you control in the cloud, receiving hits and forwarding them to vendors instead of running in the browser. looks like the web container you know, but a few pieces are unique to it. Learn these four and the rest falls into place.
Clients
A client is the part that claims an incoming request and turns it into one or more events. The GA4 client, for example, recognizes requests sent by the GA4 tag and parses them into a structured event. Clients are the server container's "listeners": nothing happens until a client claims the request.
The event data object
Once a client parses a request, it produces an event data objectevent data objectThe clean, normalized representation of a hit that a server-side client produces; server-side tags and variables read from it, much like the dataLayer on the client., a clean, normalized representation of the event (name, parameters, user data). Server-side tags and variables read from this object, much like the dataLayer on the client.
Tags
Server-side tags take the event data and forward it to a destination: the GA4 tag relays to Google's servers, the Meta CAPI tag sends to Meta, and so on. They fire on triggers, exactly like client-side tags.
The tagging server URL
This is the public endpoint of your server container (for example https://sst.example.com). Your client-side GA4 tag points its server_container_url here, and Tag Assistant connects to it for debugging.
Key takeaway
A client claims a request and builds an event data object; tags read that object and forward it on. The tagging server URL is the endpoint that ties the browser to your container.