TOOLRandom UUIDs on demand
Generate a single UUID or a whole batch in one click. Each is a version 4 (random) UUID produced from your browser's cryptographically secure random source, so the values are unpredictable and, for all practical purposes, guaranteed not to collide. Copy them all at once and drop them into your database, test fixtures or config.
What a UUID looks like
A UUID is a 128-bit number written as 32 hexadecimal digits in five hyphen-separated groups: 8-4-4-4-12, like f47ac10b-58cc-4372-a567-0e02b2c3d479. In a version 4 UUID the digit after the second hyphen is always 4, marking the version.
Where UUIDs are used
- Database keys — unique primary keys that can be created anywhere without coordination.
- Distributed systems — request IDs and record IDs that stay unique across many servers.
- Files & sessions — collision-free names for uploads, jobs and tokens.
Why UUIDs are practically unique
A version-4 UUID is 122 random bits, which is about 5 × 1036 possible values — so many that generating billions of them still leaves the chance of two ever colliding vanishingly small. That's what makes them so useful: any machine can mint an ID independently, offline, with no central coordinator, and still be confident it won't clash with one created elsewhere. It's the opposite of a database's auto-incrementing counter, which needs a single source of truth. Need a different kind of unique value? The hash generator produces deterministic fingerprints from input, and the random number generator handles plain numeric ranges.
Frequently asked questions
What is a UUID?
A UUID (universally unique identifier), also called a GUID, is a 128-bit value written as 36 characters. It is designed to be unique across space and time without a central authority, so different systems can generate IDs that will not collide.
What is a version 4 UUID?
A version 4 UUID is generated from random numbers. This tool uses the browser's cryptographically secure random source, so the values are unpredictable and effectively never repeat.
Are the UUIDs generated privately?
Yes. They are created entirely in your browser and are never sent to a server, so you can generate as many as you need with no logging.