User properties describe segments of your user base, such as language preference or geographic location. Analytics automatically logs some user properties. If you want to collect additional properties, you can set up to 25 additional user properties per project. See Custom user properties to learn how to set and register user properties.
User properties enhance user segmentation, but user property data is often only available server-side. The measurement protocol allows you to augment client-side measurements with server-side data, which is typically infeasible using only client-side solutions.
Reserved names
Some user property names are reserved and cannot be used in measurements:
first_open_timefirst_visit_timelast_deep_link_referreruser_idfirst_open_after_install
Additionally, user property names cannot begin with:
google_ga_firebase_
Example usage
In the following example, your CRM has a user property (customer_tier) you
would like to add to your measurements. customer_tier can be set to one of
premium or standard. To get this user property in your reports, you would do
the following:
First, have the client send an add_payment_info event along with a call to a
server API that has access to your CRM system:
client code
Your server then augments the measurement with the customer_tier user property
using the measurement protocol:
server code
This user property reports the two segments premium and standard.
See Sending events for full details on how to send events via the Measurement Protocol.