This is a jar. A jar of coins. But you could call it a Pot if you wanted...

But does it have an API? </predictable>

Yes.. monzo.com/docs/#pots

Now I have to write my 'Save the change' app :-D

Or... You could call it "Coin Jar"... And instead of an "app", how 'bout "pot"... /me winks maniacally