REST vs GraphQL vs gRPC

Three API styles with very different trade-offs in performance, flexibility, and tooling.

One screen in your mobile app shows a user, their last five orders, and the items in each order.

Built the ordinary way, that screen makes three trips to your server, one after another, because each answer tells the phone what to ask for next. On a train, at 80 milliseconds a trip, the screen sits empty for a quarter of a second before it draws anything. Two of those trips also returned forty fields to display two.

Somebody suggests a second endpoint shaped exactly for this screen. That works, and eleven screens later you have eleven endpoints and nobody remembers which app still uses which.

There are three answers to this, and they are not competing on one axis. Each is tuned for a different caller: strangers on the public internet, your own frontend teams, and your services talking to each other.