[tonyhart7]

Your app is must be popular to be having an entire universe "amount" of users lol

joke aside all of this is theorical, in practical application its literally impossible to hit it that it doesn't matters if its possible or not since you are not google scale anyway

[charcircuit]

It's not just your app. It's any other app or data provider that you may now or in the future interact with.

[tgv]

Only if the other side uses your key as theirs, and uses it to store data from many sources. I, personally, don't feel it's hardly worth considering. A primary key under your own control doesn't cost much, and is a better choice.

[Xelynega]

That's not how namespacing works though, is it?

Getting UUID 'A' from app 'X' is easily distinguishable from UUID 'A' from app 'Y'.

[charcircuit]

The point of the first U in UUID, universal, is that you don't need to use namespacing.

[tonyhart7]

Universal mean unique that uid wouldn't be used anyone else in any point in history or just universal available in one app????

because you just overreach at this point, if you can develop a better one. be my guest