Free UUID Generator

Practically yes. UUID v4 has 122 random bits, providing 5.3×10^36 possibilities. The probability of collision is infinitesimally small - lower than hardware failure while generating.

UUID and GUID are the same thing - 128-bit unique identifiers. GUID is the Microsoft term (Globally Unique Identifier), UUID is the standard term (Universally Unique Identifier).

UUID v4 for general use (most common). UUID v7 for database primary keys where sort order matters. UUID v1 only if you need embedded timestamp/MAC info.

UUIDs work in distributed systems without coordination. They do not reveal record count or creation order (v4). They can be generated client-side. Auto-increment requires central database coordination.

Random UUIDs (v4) can cause index fragmentation with B-tree indexes. UUID v7 or ULID solve this by being time-sorted. Also consider database-specific UUID types for better storage.

The nil UUID is all zeros: 00000000-0000-0000-0000-000000000000. It is sometimes used to represent "no value" or as a placeholder. It is not randomly generated.