Number of item-scoped custom parameters

Question

I have a question about the Google Support website (https://developers.google.com/analytics/devguides/collection/ga4/item-scoped-ecommerce)

"you can include up to 27 custom parameters in the items array" "Of these 27 custom item parameters, you can configure:" "10 item-scoped custom dimensions for standard properties" "25 item-scoped custom dimensions for Analytics 360 properties"

You can see it directly here: enter image description here

Why it says first that the limit of custom parameters in the array is 27 but then with the 360 property just 25?

Thank you for your support in advance, Iñaki

I was expecting a unified value

Answer 1

Ok, you know how we're not allowed to generate AI responses in SO? Apparently, Google decided not to apply that rule to their documentation.

What they mean there is that maximum custom item-level parameters in a network request is 27. Why 27? Because nobody cared to review MVP numbers and they just deployed arbitrary limits to prod.

Why would anyone have 27 item scoped dimensions in a payload when a limit is 25? Another great question. And apparently, the only sensible reason to do it is big query. The 25 item-scoped dimensions limit only applies to GA4 UI. BQ will not respect that limit and it will show all raw data sent as long as it's within the payload limit. Given that Google fixed the problem of BQ not receiving item-scoped dimensions. I stopped using GA for most of analytics, so not sure if they've fixed it yet.

Again, GA4 is still not exactly at the quality level UA used to be. Many small oddities like that. Especially in the reporting UI and logic. So it's deemed to be the best practice for GA users to not use the GA4 UI for anything but data debugging and use BQ or a different data destination for actual analysis. Many teams have something like Looker or PowerBI on top of that raw data.