UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit identifier that is practically guaranteed to be unique across space and time. It is typically displayed as 32 hexadecimal digits in five groups separated by hyphens: 8-4-4-4-12.

UUID version 4 is generated using random or pseudo-random numbers. Six bits are fixed (4 bits for the version and 2 bits for the variant), and the remaining 122 bits are randomly generated, providing approximately 5.3 × 10^36 possible values.

While not mathematically guaranteed, the probability of generating a duplicate UUID v4 is astronomically low. You would need to generate about 2.71 quintillion UUIDs to have a 50% chance of a single collision.

UUIDs are ideal for database primary keys, distributed systems, session tokens, file naming, and any scenario where you need a unique identifier without a central authority coordinating ID assignment.

UUID v1 uses timestamps and MAC addresses. UUID v3 and v5 use namespace-based hashing (MD5 and SHA-1 respectively). UUID v4 uses random numbers. V4 is the most commonly used because it requires no input and has no privacy concerns.