UUID Generator

About the UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit value used to uniquely identify objects in software systems. The format is always 32 hexadecimal digits in the pattern xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, grouped as 8-4-4-4-12 characters separated by hyphens.

UUID v4 is the most widely used version. Each UUID v4 is generated from random numbers, making collisions statistically impossible — there are 2¹²² possible v4 UUIDs. Use v4 when you need a unique ID and don't need to extract a timestamp from it. This generator uses the browser's crypto.randomUUID() API for cryptographically random output.

UUID v1 is time-based. The timestamp of generation is encoded into the UUID, which means v1 UUIDs from the same machine are sortable by creation time. Use v1 when ordering by creation time matters, such as in distributed databases like Cassandra.

Common uses for UUIDs: primary keys in databases, session tokens, correlation IDs in logs, idempotency keys for API requests, file names that must not conflict, and any situation where two systems need to independently generate unique IDs without coordinating.

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