Free UUID / GUID Generator
This UUID generator creates RFC 4122 version 4 (random) Universally Unique Identifiers instantly in your browser. Generate a single UUID or a bulk list, then copy them with one click.
Need a secret rather than an identifier? The Random Token Generator is built for that, and the Mock JSON Generator will populate a test fixture with UUIDs for you.
How to use the UUID Generator
- 1 Choose how many UUIDs you need.
- 2 Select the version — v4 is random and the usual choice; v7 is time-ordered and sorts better as a database key.
- 3 Generate, then copy the list in plain text, or in a quoted or comma-separated form for pasting into code.
- 4 Check the format options if you need uppercase or braces.
How to Use
Choose how many UUIDs you need, pick your preferred format, then click Generate. Every value is created locally on your device using cryptographically secure random numbers — nothing is sent to a server.
- Version 4 (random) UUIDs — the most common type
- Bulk generate up to 500 at once
- Uppercase, braces, and hyphen-free output options
- Copy all results with a single click
What is a UUID?
A UUID (Universally Unique Identifier), also called a GUID, is a 128-bit value formatted as 32 hexadecimal digits in five hyphen-separated groups: 8-4-4-4-12, for example 123e4567-e89b-12d3-a456-426614174000. Because the random space is so large, collision risk is effectively zero for practical purposes, making UUIDs ideal for database keys, session IDs, and distributed systems.
Frequently asked questions
Can two UUID v4 values ever collide?
In theory yes, in practice no. A v4 UUID has 122 random bits, so you would need to generate about 2.7 × 10¹⁸ of them before a 50% chance of any collision — far beyond any realistic system.
Should I use UUID v4 or v7 as a database primary key?
v7 for new systems. v4 is random, which scatters inserts across the whole B-tree index and hurts write performance. v7 puts a timestamp first, so IDs are roughly sequential and index locality is far better.
Is a UUID safe to expose in a URL?
It is unguessable, but it is an identifier, not a security token. Treat it as public: always enforce authorisation on the server rather than relying on nobody being able to guess the ID.
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