Generador de UUID / GUID (v4)

A version 4 UUID is 122 random bits formatted as 36 characters. Because it is random rather than sequential, two machines can generate identifiers independently and never collide in practice — which is why UUIDs are the default primary key when rows are created in more than one place. This generator uses your browser cryptographic random source, not Math.random.

Cómo usarlo

1. Set how many identifiers you need — one for a quick test, hundreds for seeding a table.
2. Press Generate. A fresh batch appears immediately; nothing is cached or reused.
3. Copy the whole block, or send it straight to a paste if you need to share it.
4. Paste them wherever you need them. Every value is independent, so you can split the list across systems.

Preguntas frecuentes

Are these really unique?

Practically, yes. With 122 random bits you would need to generate about 2.7 quintillion UUIDs before a 50 percent chance of any collision. That is not a risk worth engineering around.

Is Math.random used?

No. The tool calls crypto.randomUUID where available and falls back to crypto.getRandomValues. Math.random is predictable and would defeat the purpose.

Should I use a UUID as a database primary key?

It depends. UUIDs avoid coordination between servers, but random v4 values scatter across the index and hurt insert performance on large tables. If that matters, look at UUIDv7 or ULID, which keep time ordering.

What do the version and variant digits mean?

The 13th character is always 4, marking version 4, and the 17th is 8, 9, a or b, marking the RFC 4122 variant. Those six bits are fixed, which is why it is 122 random bits and not 128.