[hombre_fatal]

Why would you make an http request if you can just google a 3-line JS solution? You're just generating a large random number and formatting it as a UUID.

https://gist.github.com/jed/982883

If you google "generate uuid javascript" you can find approaches from Math.random to node/browser `crypto` module to shelling out OS random.

One of the main benefits of guid generation is that you don't need to synchronize with anything to generate a unique ID, so it's weird to incur an http request, especially to someone else's service. At that point you might as well just phone home to your own service.

[tatersolid]

JavaScript Math.random() should never be used for UUID generation. You will get collisions even at small scale.

window.crypto.getRandomValues() should be used instead.

The quality and seeding of Math.random() is implementation-dependent and not generally good enough everywhere to prevent collisions. Many seed with the just the system time.

Source: I have personally seen such collisions in a production web app with 700k users. A Web search for “Javacsript GUID collision” shows that many others have as well. We switched to the cryptographic generator and the collisions disappeared.

[sk0g]

UUIDs also have a hashed namespace in them, don't they? Not sure if that version implements them.

[hombre_fatal]

Only uuid v3/v5. Anything is possible if that's what you want. But 128 (or 122) bits of random are usually what you want when you think of guid.

Most people format 128-bit random numbers into a UUID just so it's obvious at a glance what it is: a guid. Even if it's not technically a UUIDv4 because it doesn't have the magic bits.