Question 1

Are these UUIDs truly unique?

Accepted Answer

UUID v4 uses cryptographic randomness. The probability of collision is astronomically low — you'd need to generate 2.71 quintillion UUIDs to have a 50% chance of one duplicate.

Question 2

Which UUID version should I use?

Accepted Answer

UUID v4 (random) is the most common choice. Use v7 or ULID if you need sortable IDs. Use v5 if you need deterministic IDs from a namespace.

UUID Generator

Are these UUIDs truly unique?

Which UUID version should I use?