What is UUID?

UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122. A UUID is typically displayed as 32 hexadecimal digits in five groups (8-4-4-4-12), e.g., 550e8400-e29b-41d4-a716-446655440000. UUIDs are designed to be unique without central coordination, making them suitable for distributed systems, database primary keys, and session IDs. Version 4 (random) UUIDs are the most common—they use random or pseudo-random bits. UUIDs are practically unique; collision probability is negligible.