Setting User IDs
A user ID should be set for each of your users. These should be unchanging and accessible when a user opens the app. Something like a username, or a unique identifier from your database is usually a good reference to use. We strongly recommend providing this identifier. It will allow you to:
- Track your users across devices and platforms, improving the quality of your behavioral and demographic data.
- Import data about your users using our User API from any source.
- Target specific users with our Messaging API for both general and transactional messages.
If such an identifier is not available, Braze will assign a unique identifier to your users, but you will lack the capabilities above.
Assigning a User ID
You should make the following call as soon as the user is identified (generally after logging in) in order to set the user id:
Do not call
ChangeUser()when a user logs out.
ChangeUser()should only be called when the user logs into the application. Setting
ChangeUser()to a static default value will associate ALL user activity with that default “user” until the user logs in again.
Additionally, we recommend against changing the user ID when a user logs out, as it makes you unable to target the previously logged-in user with reengagement campaigns. If you anticipate multiple users on the same device, but only want to target one of them when your app is in a logged out state, we recommend separately keeping track of the user ID you want to target while logged out and switching back to that user ID as part of your app’s logout process.
Automatic Preservation of Anonymous User History
|Identification Context||Preservation Behavior|
|User has not been previously identified||Anonymous history is merged with user profile upon identification|
|User has been previously identified in-app or via API||Anonymous history is not merged with user profile upon identification|
Additional Notes and Best Practices
Please note the following:
- If your app is used by multiple people, you can assign each user a unique identifier to track them.
- Once a user ID has been set, you cannot revert that user to an anonymous profile
- Do Not change the user ID upon a user “log out”.
- Doing so separates the device from the user profile. You will be unable to target the previously logged out user with re-engagement messages. If you anticipate multiple users on the same device, but only want to target one of them when your app is in a logged out state, we recommend separately keeping track of the user ID you want to target while logged out and switching back to that user ID as part of your app’s logout process. By default, only the last user that was logged in will receive push notifications from your app.
- Switching from one identified user to another is a relatively costly operation.
- When you request the user switch, the current session for the previous user is automatically closed and a new session is started. Furthermore, Braze will automatically make a data refresh request for the News Feed, in-app messages, and other Braze resources for the new user.
If you opt to use a hash of a unique identifier as your userID take care to ensure that you’re normalizing the input to your hashing function. For example,if you’re going to use a hash of an email address, ensure that you’re stripping leading and trailing whitespace from the input, and taking localization problems into account.