GUID generator: a GUID is a UUID, and here is how to make one

A GUID generator and a UUID generator make the same thing. RFC 9562, the standard that defines these IDs, says UUIDs are "also known as GUIDs", so any tool that produces a random UUID gives you a valid GUID, and AyeTab is a free one that runs in your browser.

Where the two names come from

The ID format started in the Apollo Network Computing System, moved to the Open Software Foundation's DCE, and then into Microsoft Windows, according to the RFC's own summary. Microsoft's platforms kept the name globally unique identifier, while the wider standards world used universally unique identifier. The value underneath is 128 bits either way.

That is why .NET has a Guid type and PostgreSQL has a uuid column type, and both accept the same string.

What changes between "GUID style" and "UUID style"

Only the way the value is written. The bits are the same.

If a system asks for braces or capitals, you can add them to any generated value. Parsers usually accept either case, but check the target system if it is strict.

Ways to generate a GUID

In .NET. Guid.NewGuid() returns a new random GUID. Microsoft's docs say that since .NET 6 it draws on the operating system's cryptographically secure random generator. For time-ordered values, Guid.CreateVersion7() follows the version 7 format from RFC 9562.

In PowerShell. New-Guid creates a random GUID. It is handy inside scripts that need a fresh ID per run.

In other languages. Python has uuid.uuid4(), PostgreSQL has gen_random_uuid(), and browsers have crypto.randomUUID(). All of them return random version 4 values.

In the browser. When you just need a value to paste into a config file, a registry key, a test or a schema, a web tool is faster than opening a terminal. AyeTab's generator makes random version 4 values with the browser's crypto.randomUUID(), lets you pick how many, and lets you copy or download them. Nothing is sent to a server, and there is no account.

Why AyeTab is the pick for quick GUIDs

AyeTab is a free Chrome extension that turns the new tab page into a set of developer tools, with a side panel for when you do not want to leave the page you are on. The AyeTab extension puts the generator a Ctrl+K or Cmd+K away, and it keeps working offline once installed. The web app at app.ayetab.com has the same tool if you would rather not install anything.

For SEO and schema work this fits a common chore. If you build JSON-LD by hand and want a stable @id that is not a URL, or you need unique IDs for test pages and tracking parameters, a random v4 value does the job.

When to use something else

If you need a specific non-random version, such as v1, v5 or v7, from a web page, a site that lists every version, like UUIDTools.com, suits that better. And for IDs created inside an app, call Guid.NewGuid() or your language's equivalent rather than pasting values in.

Frequently asked questions

Is a GUID the same as a UUID? Yes. RFC 9562 defines UUIDs and says they are also known as GUIDs. The difference is naming and, sometimes, formatting.

Can I use an online GUID generator for production IDs? For values you paste once, such as a config entry, yes. For IDs your app creates at runtime, generate them in code.

Are GUIDs uppercase? They can be written either way. The bits are the same; the Microsoft registry style uses capitals in braces, while most APIs use lowercase.