It depends how you do micro services. There are middle grounds. One big gain of micro-services is that it guarantees things are separate and can be handled by separate teams if the need arises. That doesn't mean you need to start out that way. For instance in Python I use hug to create my microservices https://github.com/timothycrosley/hug, then I can just install them to create a "monolithic" services that consumes all the microservices, the great thing is that hug allows you to expose both as a webservices, and as a Python library so I can consume as a Python library with no overhead, until the need to split is evident, and then can split up the services with very little work. Of course the need may never arrive, but the modularity that is forced when using micro-services pays dividends quickly regardless