Almost all service middleware is capable of running tasks in multiple threads so when serving lots of users that's a very easy way to get parallelism. If you're

Almost all service middleware is capable of running tasks in multiple threads so when serving lots of users that's a very easy way to get parallelism. If you're just copying data around (like in an HTTP API implementation) you're mostly I/O bound anyway and adding more compute won't help that much so there's no return on investment.