UUID Generator
Generate cryptographically secure RFC 4122 / RFC 9562 v4 UUIDs, bulk generate up to 1000 UUIDs, validate syntax, and inspect structural versions locally.
What Is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier, conventionally written as 32 hex digits in five hyphen-separated groups, designed to be generated independently by many systems with a negligible chance of collision. This tool generates version 4 (random) UUIDs, and can also validate and inspect the structure of any UUID you paste in.
How to Use the UUID Generator
- Generate one or many UUIDs at once.
- Choose a formatting option (with or without hyphens, uppercase/lowercase).
- Or paste an existing UUID into the validator/inspector to check its format and view its version and variant bits.
- Copy individual or bulk results.
Technical Notes
- Version 4 UUIDs are generated from random bits (using a CSPRNG here), not derived from timestamps or hardware identifiers — they reveal nothing about when or where they were created.
- UUIDs are identifiers, not secrets — they're unique, not unguessable enough to serve as an access token or password.
Frequently Asked Questions
Are UUIDs secret or hard to guess?+
No. A version 4 UUID has 122 random bits, so collisions are effectively impossible, but it is an identifier, not a credential. Never use one as a session token, password-reset token, or API key.
What is the difference between the UUID versions?+
Version 1 encodes a timestamp and a node identifier; versions 3 and 5 are hashes of a namespace plus a name (MD5 and SHA-1 respectively); version 4 is fully random. This generator produces version 4; the inspector reads the version and variant bits of any UUID you paste.
Can two version 4 UUIDs ever collide?+
In theory yes, in practice no. You would need to generate on the order of 2.7 quintillion (2^61) version 4 UUIDs before reaching a 50% chance of a single collision. The values here come from the browser cryptographic RNG, not Math.random().