UUID Generator

Random UUID

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v4

a98fc0c1-8f26-413b-86c1-16d1860263fe

Time based UUID

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v6

1f1138c8-8cde-64a0-9cf9-8903b74df904

UUID v7

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Time + Random

Uses a 48-bit Unix epoch timestamp (millisecond precision) followed by random bits. Time-sortable and optimized for better database indexing than V1. Considered the modern best practice.

019c9d24-ffea-7578-8c54-2b3a782151d1

UUID v6

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Reordered Time-based

Time-based like V1 but reorders the bits to be monotonically increasing (better for database indexing). Does not expose the MAC address (often uses a random node ID instead).

1f1138c8-8cde-64a1-951c-2f6fd93b57df

UUID v4

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Random (Pseudo-random numbers)

Maximum unpredictability and privacy. Not sortable by time. Higher (but still very low) theoretical collision chance compared to time-based.

166ab571-2ba9-4b73-a732-f247fe358574

UUID v1

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Time-based + MAC Address

High uniqueness, sortable by time. Privacy concern due to including the generating machine's MAC address.

88cde4a2-138c-11f1-9cf9-8903b74df904