This is really tangential, sorry, but I'd like to mention that the (US) military is strongly opinionated in a relatively small number of ways. Additionally, the rules are self-enforced throughout most of its structure, and almost none of the rules being broken will cause the system or its components to fail. The US military is actually incredibly flexible, because the (mostly) self-enforced strong opinions inform the decisions of subsets of the military all the way down to the individual level, allowing each component to be effective almost regardless of the health of the rest of the system. SOAP was incredibly inflexible. I think perhaps a better analogy would be to compare SOAP to some defense contractors, where things must work a certain way, or they grind to a halt and become very expensive to debug and triage. Also, incidentally, I'm interested to hear about your experiences with gRPC. I have just played with it, but it sounds like you had some issues scaling with it? Or didn't like it so much? I much prefer REST because of its inherent flexibility, as you do, but I am interested to hear from people who scaled with gRPC.