That's called sharding and is pretty widely used nowadays. There is even readily available middleware that handles this for you, so no need to put it into the backend.
Keep in mind this is more than a decade ago. Sharding was almost certainly state-of-the-art and exotic back then (hell, it's arguably pretty unusual in the wild even today, even if a lot more mature of a concept).
Oh, of course! I did not wish to come of as arrogant. I just wanted to add the term (for easier googling if someone is interested) and a note that it's no longer necessary to modify your api to use that strategy.
That's called sharding and is pretty widely used nowadays. There is even readily available middleware that handles this for you, so no need to put it into the backend.