I'd like to point out that the article does mention that their system is not single process. They have a database, caching layer and web servers at the very lea

I'd like to point out that the article does mention that their system is not single process. They have a database, caching layer and web servers at the very least which could be run on a single box. The number of API calls is a matter of degree when compared with a microservices architecture. A microservices approach does not mean that they should run on different hosts and an early design decision should be that the entire architecture can run on a single host and that the scale out is a feature of the system. It's worrying that this assumption is often made because it does lead to the maintenance and velocity issues that teams encounter when naively adopting microservices.