Free UUID Generator
Generate cryptographically secure v4 UUIDs. Click to copy any UUID.
The UUID Generator creates cryptographically secure v4 UUIDs, and you can click any value to copy it. Use it for unique identifiers in apps, databases, and testing.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit number written as a string of hexadecimal digits in the 8-4-4-4-12 format, for example 550e8400-e29b-41d4-a716-446655440000. Version 4 is the most common type: its value is essentially random, which means the chance of two independent UUIDs colliding is astronomically small, so you can generate one on any machine without ever checking it against a central registry. The 128-bit structure consists of 32 hexadecimal characters separated by hyphens in the pattern 8-4-4-4-12, where 122 bits are randomly generated and 6 bits are fixed to indicate version 4. This standardized format ensures UUIDs work universally across programming languages, databases, and operating systems.
UUIDs are everywhere in modern software. They are a popular choice for database primary keys, session and request identifiers, event and log IDs, and unique handles in distributed systems, precisely because any device can create a valid one locally and safely. That makes them ideal for microservices, offline apps, and any situation where a shared counter or ID server would be a bottleneck or a single point of failure. The JavaScript implementation in this tool uses the Web Crypto API (crypto.getRandomValues) which provides cryptographically secure random numbers from your browser's underlying system, far superior to Math.random() for uniqueness guarantees.
This generator creates version 4 UUIDs using your browser's cryptographic random source, so the values are high quality. It runs entirely in your browser: nothing you generate is sent to a server, and it is free with no account or limits. The algorithm sets specific bits to mark the UUID as version 4 (setting bits 12-15 of the 7th byte to 0100) and variant 1 (setting bits 6-7 of the 9th byte to 10), then fills the remaining bits with random values from crypto.getRandomValues(new Uint8Array(16)). You can generate 1, 3, 5, 10, or 20 UUIDs at once, click any one to copy it, or copy the entire batch with a single action.
How to use this UUID Generator
- Choose how many UUIDs you need.
- Click Generate to produce a fresh batch.
- Copy a single value or copy the whole list at once.
FAQ
What is a UUID?
UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify items. Version 4 UUIDs are randomly generated and have a 122-bit random component.
Are these UUIDs truly random?
Yes, they use the Web Crypto API (crypto.getRandomValues) for cryptographically secure random generation.
Is this UUID generator free?
Yes, completely free with no limits.
Are the UUIDs I generate tracked or stored?
No. UUIDs are generated in your browser and nothing is uploaded or stored.