I just came across an interesting new blog post by the great Simo Ahava. If I understood it correctly, this GTM update introduces the possibility to take an incoming data stream request and route it to multiple streams. This could be a game-changer for building a roll-up property using just a single GA4 instance as a proxy.
Here’s the key part that caught my attention:
“Until recently, that is. A late-2024 update to server-side Google Tag Manager automatically fetches relevant GA4 configuration settings for each outgoing request that has its Measurement ID overridden in the GA4 tag settings in server-side Google Tag Manager.”
I’m planning to test this out soon, and I’d love to hear your thoughts. Do you see any potential issues with this approach, or maybe some limitations I should watch out for?
I also haven’t tested this yet, but it sounds like something that would really make it a lot easier to set up a rollup property for the GA4 server side
Not sure if this is exactly what you’re looking for, but we use sGTM to send a data stream to multiple GA4 properties from a single website.
Our setup is regional—each regional store is on a subdomain of the same TLD—so we needed a separate GA4 property for each region, plus one global GA4 property to track everything together.
Our implementation is actually simpler than what’s described in the article you shared. We use a single Google Tag and GA4 event tag on the client side (using the regional measurement ID). Then, on the server side, we configure 2 GA4 tags with different measurement IDs and send all event parameters and user properties to both.
We’ve compared regional and global data multiple times (filtering the global data by subdomain to match), and the differences are minimal.
Hope this helps anyone looking to use multiple GA4 properties on a single website. There is barely any documentation on this out there and we had to figure out by ourselves.
That said, this setup might not be perfect—so if anyone has suggestions or improvements, I’d love to hear them. Thanks!