Question 1

What is a UUID?

Accepted Answer

UUID stands for Universally Unique Identifier. It is a 128-bit label standardised as RFC 4122 and used to uniquely identify resources in software systems, databases, and APIs.

Question 2

What is the difference between UUID v4 and other versions?

Accepted Answer

v4 UUIDs are randomly generated, making them ideal for general use. v1 embeds the machine MAC address and timestamp, which can leak system information. v5 is deterministic and hash-based. v4 is the most widely used.

Question 3

Are v4 UUIDs truly unique?

Accepted Answer

Statistically yes. The probability of generating two identical v4 UUIDs is approximately 1 in 2¹²² — roughly 5.3 × 10³⁶. In practice, collisions are effectively impossible.

Question 4

What is the difference between a UUID and a GUID?

Accepted Answer

They are the same concept. GUID (Globally Unique Identifier) is Microsoft's name for UUID. The format, structure, and generation method are identical.

Question 5

Can I generate multiple UUIDs at once?

Accepted Answer

Yes. Set the batch size to generate up to 100 UUIDs at once, all cryptographically random and ready to copy as a list.