Modules vs Microservices, January 2023 edition I've done monoliths and microservices. I've worked in startups, SMEs and at FAANGS. As usual, nothing in this ar

Modules vs Microservices, January 2023 edition I've done monoliths and microservices. I've worked in startups, SMEs and at FAANGS. As usual, nothing in this article demonstrates that the person has significant experience of running either in production. They may have experience of failure. In my experience, microservices are simply one possible scaling model for modules. Another way to scale a monolith is to just make the server bigger: the One Giant Server model. If you have a fairly well defined product, that needs a small (<30) number of engineers, then the One Giant Server model might be best for you. If you have a wide feature set, that requires >50 engineers, then microservices is probably the way to go. There is no noticeable transition from a well implemented monolith with a small team into a well implemented Giant Server with a small team. Possibly some engineers are worrying about cold start times for 1TB of RAM, but that's something that can happen well ahead of time, and hardware qualification is something one needs to do for microservices too. Some of the best examples of Giant Servers are developed by small teams of very well paid developers. The transition from a monolith to a set of microservices, however is a very different affair. Unfortunately, the kind of projects that need to go microservices are often in a very poor state. Many such adventures one reads about are having to go to microservices because they've already gone to One Giant Server and those are now unable to handle the load. Usually these stories are accompanied by a history of blog posts about moving fast and breaking things, yolo, or whatever is cool. The transition to microservices is difficult because there are no meaningful modules: no modules, or modules that all use each other's classes and functions. I don't believe that, once a particular scale is reached, microservices are a choice. They are either required or they are not. Either you can scale successfully with One Giant Server, or you can't. The problem is that below a certain scale, microservices are a drag. And without microservices, it's very easy for inexperienced teams to fail to keep module discipline.