UUID Generator Guide — What Are UUIDs and How to Use Them

Understand UUIDs and learn how to generate UUID v4 and v7 with our free online tool.

What is a UUID?

A UUID is a 128-bit number used to uniquely identify information in computer systems. It is standardized by RFC 9562.

UUIDs are used as database primary keys, session IDs, transaction IDs, and in distributed systems.

UUID v4 is randomly generated. It is the most widely used version.

UUID v7 is time-ordered with millisecond precision, ideal for database indexes as it reduces index fragmentation.