Which UUID version should I use most of the time?
v4 is usually the default choice for random unique identifiers.
UUID / GUID Generator
Generate UUIDs in v1, v4, or v5 — bulk, formatted, with optional prefix/suffix.
UUID Selection Notes
Different UUID versions serve different needs. Picking the right version improves traceability, interoperability, and deterministic behavior.
- Use v4 for general random identifiers.
- Use v1 when time ordering is useful and acceptable.
- Use v5 for deterministic IDs from namespace plus name.
Related tools: Hash Generator, Number Base Converter, Password Generator.
UUID Generator FAQ
Why does v5 require namespace and name?
v5 derives output deterministically from those two inputs.
Can I generate many UUIDs at once?
Yes. Bulk generation is useful for seed data and test fixtures.