Is the User ID case-sensitive in Pushwoosh?

Yes. Pushwoosh stores and matches User IDs exactly as you send them, without changing their case or trimming them. User123 and user123 are two different users, each with their own devices and user-specific tags.

What happens if the case doesn't match

• Sending to users. A message sent via the users parameter to User123 does not reach the devices registered for user123. The message completes normally but has 0 recipients, and no error is returned.
• Reading user data. A request with a different case returns "user not found", even though the user exists.
• Registration. Calling registerUser / setUserId with a different case creates a new user instead of updating the existing one.
• CSV import. Tag names in the CSV header are matched regardless of case, but User ID values are matched exactly.

How to avoid it

Pick one canonical form of your User ID (for example, always lowercase) and use it everywhere: in the SDK (setUserId), in API requests, and in CSV imports. If you already have users registered in mixed case, send messages using exactly the IDs that are stored in Pushwoosh.

Related articles

• How do I send a push notification to a specific user by User ID or to a single device by HWID?
• Why am I getting an 'Unknown Devices' error with the createMessage API, and are parameters case-sensitive?