Looking at Uber's APIs they're built to be sharded. But sharding comes at the cost of complexity. I work on an uber-like service and we use crude sharding bet

Looking at Uber's APIs they're built to be sharded. But sharding comes at the cost of complexity. I work on an uber-like service and we use crude sharding between countries. The problem is: * sometimes your sharding is too coarse - eg. two cities which have no cross traffic * sometimes your sharding is too fine - eg. cross border traffic But the real complexity is; * managing configuration and logic differences between countries and cities * hosting so many different sharded clusters, routing between them, and keeping them all updated. And that's where all the work goes.