Even what's referred to as a "monolith" is usually implemented as multiple services. Most Django and Rails apps have at least a database on the backend and an h

Even what's referred to as a "monolith" is usually implemented as multiple services. Most Django and Rails apps have at least a database on the backend and an http server/reverse proxy on the frontend. And there are good, logical reasons why 3 tiers works - the data, logic, and network resources all have different operational and development cycles. But 4 or 5 or 10 tiers might be just as appropriate for your problem domain. A data boundary may force a split. A different language or different hardware required (GPU) might force a split. Split services off for an actual reason, not because of fashion trends! It's not rocket science but it does require critical thinking.