What Are the Differences Between UUID, ULID, KSUID, and Snowflake IDs, and How Do I Choose?

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What Are the Differences Between UUID, ULID, KSUID, and Snowflake IDs, and How Do I Choose?

UUID, ULID, KSUID, and Snowflake ID are all schemes for generating globally unique identifiers.

In brief, UUIDs are 128-bit random identifiers, ULIDs and KSUIDs are time-encoded identifiers (128-bit and 160-bit respectively) that sort in creation order, and Snowflake IDs are 64-bit numeric identifiers combining a timestamp, machine ID, and sequence counter.

Each format trades off size, readability, and ordering guarantees to suit different distributed-system needs.

What is a UUID?

A UUID (“Universally Unique Identifier”, also known as GUID) is a 128-bit valu

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