Understanding UUIDs

UUIDs (Universally Unique Identifiers) are 128-bit identifiers that are guaranteed to be unique across all systems and time. They're essential for distributed systems, databases, and applications requiring unique identification.

UUID Versions

There are different versions of UUIDs, each with its own generation method and use cases:

Version 4 (Random)

Generated using random or pseudo-random numbers. This is the most commonly used version as it doesn't expose any information about the machine or time it was created. Recommended for most applications.

Version 1 (Timestamp-based)

Generated using the current timestamp, clock sequence, and MAC address. While it guarantees temporal uniqueness, it can expose information about when and where it was created.

UUID Format

All UUIDs follow the standard format: 8-4-4-4-12 hexadecimal digits, separated by hyphens. For example: 550e8400-e29b-41d4-a716-446655440000. The total length is always 36 characters including hyphens.

Common Use Cases

UUIDs are commonly used as primary keys in databases, session identifiers, file names, API request IDs, and anywhere you need a unique identifier that doesn't require central coordination.

UUID Generator