UUID Generator
Create random RFC 4122 version 4 UUIDs. Choose how many you need and copy them instantly; they are generated locally in your browser.
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About the UUID Generator
A UUID (universally unique identifier), also called a GUID, is a 128-bit value written as 32 hexadecimal digits in the pattern 8-4-4-4-12, for example 3f2504e0-4f89-41d3-9a0c-0305e82c3301. This tool produces version 4 UUIDs, where almost all of the bits are random. The odds of two independently generated v4 UUIDs colliding are vanishingly small, which is why they are used as database keys, request IDs, file names and idempotency tokens without any central coordination.
How to use it
- Choose how many UUIDs you need - one, or a batch for seeding test data.
- Generate, then copy a single value or the whole list with one click.
- Paste them straight into your code, migration script or fixtures.
The randomness comes from your browser's crypto API, so the values are suitable as unguessable identifiers. Keep in mind a v4 UUID carries no timestamp or ordering, so it should not be used where you need values to sort chronologically. Generation is entirely local - nothing about the UUIDs you create is sent to or stored on a server.
Frequently asked questions
What is a version 4 UUID?
A version 4 UUID is an identifier whose bits are almost entirely random, apart from a few fixed bits that mark the version and variant. It is the most common UUID type because it needs no central authority and no input data to generate.
Can two generated UUIDs ever be the same?
In theory yes, but the probability is astronomically small. With 122 random bits you could generate billions of v4 UUIDs and the chance of a collision remains negligible, which is why they are treated as effectively unique.
What is the difference between a UUID and a GUID?
They are the same thing. GUID is Microsoft's name for the identifier, while UUID is the term used in the RFC 4122 standard. The format and behaviour are identical.
Are these UUIDs generated privately?
Yes. They are created in your browser using the local crypto random source. No values are sent to a server or stored anywhere, so you can safely use them as secret identifiers.