A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as 32 hexadecimal digits in 5 groups: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. The '4' indicates version 4 (random).

Are v4 UUIDs truly unique?

Statistically, yes. The probability of generating two identical v4 UUIDs is astronomically low — you'd need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of a single collision.

UUID vs GUID — what's the difference?

They're the same thing. UUID is the standard term (RFC 4122). GUID (Globally Unique Identifier) is Microsoft's name for the same concept.

When should I use UUIDs?

Use them as database primary keys, API resource identifiers, session tokens, correlation IDs for distributed systems, and anywhere you need a unique identifier without a central authority.

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Generate cryptographically random v4 UUIDs instantly. Supports bulk generation, uppercase, and no-dash formats.

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