User ID reference
Users may interact with your website or application from a number of different devices, such as a desktop web browser, a browser on a mobile phone, or via a native mobile application. By default, Analytics assigns each device a unique Client ID, and considers each unique Client ID as a unique user in your reports. User ID enables holistic measurement of user interactions that span across devices, such as attributing an interaction with a marketing campaign on one device to a conversion that occurs on another device, or de-duplicating unique users across multiple devices.
The User ID feature consists of:
userIdfield, which can be set to a stable, non-personally identifiable ID to represent a unique user.
- Cross-device reports that provide insight into behavior and conversion paths across devices.
When User IDs are sent with Analytics hits in the
userId field, your reports
will reflect a more accurate count of unique users and offer new cross-device reporting options.
This article describes how you can configure and send User IDs to Analytics, as well as how User ID data is processed and reported in your User ID-enabled views.
Before sending User IDs to Analytics, you must enable at least one reporting view for User ID.
Enabling a view for User ID produces two effects on that view:
- New and unique users are calculated using unique User IDs rather than unique Client IDs.
- Cross-device reports that leverage the User ID will be enabled in that view.
userIdfield was set.
When a user is known to your website or application, you should send an ID representing that
user with all of your Analytics hits, such as pageviews, events, ecommerce
transactions, etc., using the
It is up to you to provide the ID. These IDs typically come from an authentication system, in which each signed-in user account has a stable, and unique ID with which it is associated, and should have the following characteristics:
- Non-personally identifiable
- Unique to a user of your service or app
- Persistent for a signed-in user across all devices
For more information on how to set
userId in a particular environment, see the
Collection APIs and SDK dev guide for your specific library.
Analytics hits, like pageviews, events, or transactions, for which the
userId field has been set, are processed separately from non-userId hits and will
only be visible in User ID-enabled views (profiles).
For example, if a User ID is set in the middle of an existing Analytics session, the session will begin with the first hit in which the User ID is set for User ID-enabled views (profiles).
Non-User ID views (profiles) would report the entire session without regard for the
After processing, session data for which
userId was set is available for
User ID-enabled views (profiles) in Cross-Device reports. Although the session data is available via
the Core Reporting API, the
userId field is not available as a dimension in
reports and can not be exported from Analytics.
New and Unique user metrics will also be based on User ID in these views (profiles).
In non-User-ID-enabled views (profiles), these metrics will be calculated
Client ID vs. User ID
The following table summarizes the differences between Client ID and User ID:
|Client ID||User ID|
|What does the ID Represent?||An anonymous device or browser instance.||A single user, like a signed-in user account, that may interact with content across one or more devices and / or browser instances.|
|How is the ID Set?||Randomly generated and automatically sent with all hits by Analytics libraries.||You must set and send your own
|How is ID Used to Calculate Unique Users?||In a non-User-ID-enabled view (profile), Client ID is used to calculate unique users.||In a User-ID-enabled view (profile), User ID is used to calculate unique users|
The following limits are currently in place for the User ID feature:
- Cross-device reports enabled by the User ID feature have a maximum date range of 90 days.
- The User ID value can not be queried as a dimension in reports in either the web interface or the APIs.