[mdedetrich]

It most definitely can be because the design of the protocol can force a bound on how performant it can be. While its true that certain implementations of HTTP can be faster or slower, even the best implementations of HTTP 1.1 (for example) are quite slow when you compare it to the alternatives.

I know this because I worked at a place which was entirely based around microservices using Rest HTTP as the protocol/interface, some teams had to use alternate methods because HTTP protocol was the bottleneck.