What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit value used to uniquely identify information without requiring a central authority to issue it. It's commonly used as a database primary key, session ID, or unique identifier in distributed systems.

Is this a version 4 (random) UUID?

Yes. Every UUID generated by this tool is a version 4 UUID, meaning it is generated using random or pseudo-random numbers via the browser's crypto.randomUUID() API, as defined in RFC 4122.

Are the UUIDs generated on my device?

Yes. Every UUID is generated locally in your browser using the Web Crypto API. Nothing is sent to a server, and no UUID is ever logged or stored.

Can two generated UUIDs ever collide?

In practice, no. A version 4 UUID has 122 random bits, giving about 5.3 × 10^36 possible values. You would need to generate roughly 2.71 quintillion UUIDs before there's a 50% chance of a single collision — a number far beyond any realistic use case.

Can I generate more than 1,000 UUIDs at once?

This tool limits a single batch to 1,000 UUIDs to keep the page fast and easy to copy. For larger batches, run the generator multiple times, or use crypto.randomUUID() directly in a script.

What's the difference between UUID and GUID?

They're effectively the same thing. GUID (Globally Unique Identifier) is Microsoft's name for the same 128-bit identifier format standardized as UUID in RFC 4122. Values generated here work as either a UUID or a GUID.