UUID Generator

A fresh v4 UUID, one click away.

Generate a random version-4 UUID (universally unique identifier) for use in code, databases or configs.

How it works

A version-4 UUID is 122 random bits formatted as 32 hexadecimal digits in five groups (8-4-4-4-12), with a few bits set to mark the version and variant.

When it helps

UUIDs are used as unique IDs in databases, APIs and distributed systems without needing a central counter.

Anatomy of a UUID

A UUID looks like 3f2b8c1e-9d4a-4e7b-a1c2-5f6e7d8c9b0a: 36 characters, made of 32 hex digits and 4 hyphens. In a version-4 UUID, the first digit of the third group is always 4, and the first digit of the fourth group is 8, 9, a or b. Everything else is random.

With 122 random bits there are about 5.3 × 10³⁶ possible values. You could generate a billion UUIDs every second for decades without a realistic chance of a duplicate.

When to use one

UUIDs are handy as database keys when records are created on many servers or devices at once, as IDs in APIs that shouldn't reveal how many records exist, and as unique names for files or test data.

The trade-off is size and ordering: a UUID is longer than a simple number, and random v4 values don't sort by creation time, which can slow some database indexes. Newer formats like UUIDv7 address this.

Frequently asked questions

Can two UUIDs be the same?

In theory, but the chance is so small it's negligible for practical purposes.

What's the difference from v7?

Version 7 UUIDs start with a timestamp so they sort by creation time; v4 is fully random.

Is it safe to use these UUIDs as secrets?

They're generated with a secure random source, but UUIDs are designed as identifiers. For passwords or tokens, use the Password Generator.

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