📖 UUID v4 Generation & Random Entropy Guide
Learn RFC 4122 specifications, 128-bit UUID structure, collision probabilities, and cryptographically secure random number generators.
Anatomy of an RFC 4122 Version 4 UUID
A Universally Unique Identifier (UUID) is a 128-bit number formatted as 32 hexadecimal digits displayed in five groups separated by hyphens (`8-4-4-4-12`).
Version 4 UUIDs are generated using random or pseudo-random numbers. Out of 128 bits, 6 bits are reserved for variant and version markers, leaving 122 bits of pure entropy (giving 2^122 or ~5.3 x 10^36 possible unique values).
Frequently Asked Questions
Detailed specifications & guides FAQs.