A user ID is a unique identifier assigned to each user interacting with your software product. This ID helps you track user behavior and create accurate customer profiles. By capturing every user interaction, you can better understand how users engage with your software.

User IDs can be generated in several ways. Common methods include using email addresses, usernames, or random strings. Random strings are often preferred for their compatibility across different platforms. They also offer better privacy, as they don't directly expose personal information.

When you assign a user ID, you enable your system to link various actions to a specific user. This is crucial for creating a detailed user journey. It helps you identify patterns in user behavior, making it easier to optimize your product based on real-world usage.

In summary:

• User ID: Unique identifier for each user.

• Benefits: Tracks behavior, creates profiles, enhances insights.

• Generation methods: Emails, usernames, random strings.

Understanding and implementing user IDs correctly can significantly improve your analytics. They provide the foundation for deeper insights into how users interact with your product.

User IDs vs. UUIDs

What are UUIDs?

Universal Unique Identifiers (UUIDs) are 128-bit numbers globally unique. They ensure high security and privacy. Ideal for systems needing absolute uniqueness, like financial platforms.

UUIDs don't rely on a central authority to be unique. They combine timestamps and random data. This makes them nearly impossible to duplicate.

Use UUIDs to prevent data collisions. They are more secure than typical user IDs. Especially useful in sensitive applications. Learn more about other stable identifiers.

Advantages of UUIDs

• Global Uniqueness: No two UUIDs are the same.

• Security: High level of privacy protection.

• Compatibility: Works across multiple systems without conflicts.

UUIDs are not easily readable. They are best for backend systems. For user-facing elements, simpler IDs might be better. See why user IDs are required for certain use cases.

For more detailed information, check the Statsig Guide for Device Experiments and how to use stable IDs.

Examples of user ID usage

• Tracking user behavior: Assign user IDs to analyze feature interactions. This helps teams make data-driven improvements. Learn more about using stable IDs for experiments involving anonymous users and other stable identifiers.

• Creating customer profiles: User IDs build detailed profiles. Understand user preferences and behavior patterns. For example, you can experiment using custom unit ID types to ensure consistent experiences within the same organization.

• Security enhancements: Use UUIDs for user IDs in sensitive applications. This boosts security and privacy. It's important to understand why a StatsigUser with a UserID or custom ID is required for server SDKs.