What is the difference between Device ID and Distinct ID?

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Based on the knowledge sources, here are the key differences between Device ID and Distinct ID in Mixpanel:

Device ID is used to track a device while the user is in an anonymous state. According to the Simplified ID Merge documentation: - It's automatically generated by Mixpanel's client-side SDK and attached to all user events - It serves as the anonymous ID for the user before they log in or sign up - When an event contains only a $device_id (without a $user_id), the $device_id value is set as the distinct_id for that event - It persists on the user's device until .identify() or .reset() is called

Distinct ID is Mixpanel's internal unique identifier used to track a user across the entire system. As explained in the Identity Management Overview: - It's the property Mixpanel uses to determine user uniqueness - Every event and profile update should have a distinct_id associated with it - When two events have the same distinct_id, they're considered performed by the same unique user - It's used across all Mixpanel reports (Insights, Funnels, User profiles) to identify and track users

In the Simplified ID Merge API, the distinct_id is determined automatically based on the presence of $device_id and $user_id: - Before login: distinct_id = $device_id (prefixed with $device:) - After login: distinct_id = $user_id - When both $user_id and $device_id appear together for the first time, Mixpanel creates a mapping to merge them into an identity clusterIn summary: Device ID is one type of identifier (for anonymous users), while Distinct ID is the unified identifier that Mixpanel ultimately uses to track users throughout the system.

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