What is a UUID?
A UUID (Universally Unique Identifier) is a 36-character alphanumeric identifier used to give a unique identity to any collection of information within a computer system. Since the probability of duplication is extremely low, UUIDs are a widely used tool for giving a permanent and unique identity to virtually any type of data.
Version 4 UUIDs are probably the easiest to understand and perhaps the most commonly used. These UUIDs are simply randomly generated values (derived from a cryptographically secure generator) that do not contain any namespace, device, or time-based information.
They look like in the above code block .
The only non-random character in this value is the "4" in the first position of the third section (after the second hyphen), which means that it is a v4 UUID. Otherwise, every other character is just a random number from 0-9 or a lowercase letter from a-z.