Question 1

What is UUID v7?

Accepted Answer

UUID v7 is the latest time-ordered universally unique identifier defined in RFC 9562 (2024). It embeds a Unix timestamp in milliseconds, making UUIDs sortable by creation time while maintaining randomness. V7 improves upon v6 by using Unix timestamps instead of Gregorian timestamps and provides better privacy by not including MAC addresses.

Question 2

When should I use UUID v7?

Accepted Answer

Use UUID v7 for new projects requiring time-ordered identifiers. Perfect for database primary keys with optimal B-tree performance, distributed system logs, event tracking, time-series data, and any scenario where chronological sorting matters. V7 is recommended over v6 for modern applications due to its improved timestamp format and privacy features.

Question 3

What's the difference between UUID v7 and v6?

Accepted Answer

UUID v7 uses Unix timestamp (milliseconds since 1970) while v6 uses Gregorian timestamp. V7 provides better privacy as it doesn't include MAC addresses like v6. Both are sortable, but v7 is the newer standard (RFC 9562, 2024) and recommended for modern applications. V7 also has better compatibility with existing time-based systems.

Question 4

Is UUID v7 better than UUID v4?

Accepted Answer

For databases and time-ordered data, yes. UUID v7 provides the same security as v4 (cryptographically random) while adding sortability. This results in better database index performance, reduced fragmentation, and improved query efficiency. V4 is still better for purely random identifiers where time ordering isn't needed, but v7 is superior for most modern applications.

Version	Time-based	Sortable	Best Use Case
v1			Legacy systems
v4			Random IDs, security
v6			Modern databases
v7			Latest standard (2024)

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