Online Version 4 UUID / GUID generator — create one ID or a bulk set locally (nothing is uploaded).

Bulk count (max 1000)

Uppercase

Hyphens

0 Version 4 UUIDs

Quick answers

Are these UUIDs actually random, or is there a pattern?
They're generated by crypto.randomUUID(), which uses a cryptographically secure random number generator provided by your browser and operating system — the same category of randomness used for generating encryption keys, not a simple pseudo-random pattern.
Is a GUID the same as a UUID?
Yes in practice. GUID (Globally Unique Identifier) is Microsoft's name for the same 128-bit identifier family. This GUID generator outputs standard Version 4 UUID strings.

About Online UUID Generator

Free online UUID generator tool. Quickly generate individual or bulk Version 4 UUIDs (universally unique identifiers / GUIDs) with crypto.randomUUID() — RFC 4122 layout, optional uppercase or hyphen-free format, up to 1,000 per batch. Runs 100% in your browser.

This online UUID generator tool creates Version 4 UUIDs — also called random UUIDs or GUIDs in many Windows/.NET docs. Generate a single universally unique identifier or a bulk set (up to 1,000) with one click. Every value comes from crypto.randomUUID() in your browser, backed by the OS cryptographically secure random source.

A Version 4 UUID is (almost) entirely random: 122 of 128 bits are random, with the remaining bits marking version and variant per RFC 4122. That layout is the same industry standard referenced by generators like uuidgenerator.net. Collisions are not a practical concern even at the full batch size.

Other UUID versions exist (Version 1 time-based, Version 7 time-ordered, nil/empty UUID). SparkJSON focuses on the Version 4 UUID generator most APIs and databases use for unpredictable IDs. Formatting toggles only change presentation — uppercase or hyphen-free — not the underlying randomness or RFC 4122 bit layout.

Frequently asked questions

Are these UUIDs actually random, or is there a pattern?

They're generated by crypto.randomUUID(), which uses a cryptographically secure random number generator provided by your browser and operating system — the same category of randomness used for generating encryption keys, not a simple pseudo-random pattern.

Is a GUID the same as a UUID?

Yes in practice. GUID (Globally Unique Identifier) is Microsoft's name for the same 128-bit identifier family. This GUID generator outputs standard Version 4 UUID strings.

Why is there a limit of 1,000 UUIDs per batch?

It's a practical UI limit, not a security one — generating and rendering tens of thousands of rows at once would make the page sluggish for no real benefit. If you need more, just click Generate again for another bulk set.

What's the difference between UUID v4 and other versions?

UUID versions differ in how their bits are derived. Version 1 encodes a timestamp and (traditionally) a MAC address, Version 7 is time-ordered, and Version 4 — what this tool generates — is (almost) fully random, which makes it the right default when you just need a unique, unpredictable identifier.