This is pretty much what I gathered from experience but it’s much better phrased than what I could do

Another recommendation by Alex Robson at Zendesk.

it’s good to have a grasp on the fundamentals of the protocol, especially as we introduce additional services that will be communicating across the protocol. While “swagger/json api” seems like it would be good enough, there are gaps in that specification that assume you understand things built into HTTP.

Shared in Zendesk Engineering slack channel, a great recap of HTTP/[1, 2, 3]