Between migrating to micro services and using a Rule Engine, Serverless is a pragmatic approach that allows deploying business capabilities that change often. Micro services are ubiquitous. However, most companies that implement micro services do not reap their full benefits - at best. At worst, it’s an epic failure. There are reasons for micro services: independent deployment of business capabilities. However, the unspoken assumption is that you need to deploy all capabilities all the time. My experience has shown me that it’s plain wrong. Some capabilities need frequent deployment, while some are much more stable. In “the past”, we used Rule Engines to allow updating business rules without deployment. While it solved the problem, this approach had issues. Between introducing a Rule Engine and migrating your complete system to micro services, I believe that there’s a middle path, and that this path is Function-as-a-Service.