dictopen

  A microservice architecture – a variant of the  SOA (service-oriented architecture)  structural style – arranges an application as a collection of loosely-coupled services. In a microservice architecture, services are fine-grained and the protocols are lightweight. The goal is that teams can bring their services to life independent of others. Loose coupling reduces all types of dependencies and the complexities around it, as service developers do not need to care about the users of the service, they do not force their changes onto users of the service.

  Function as a service (FaaS) is a category of cloud computing services that provides a platform allowing customers to develop, run, and manage application functionalities without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app. Building an application following this model is one way of achieving a  "serverless"  architecture, and is typically used when building microservices applications.

  Lukas defines a micro  API  as a design pattern for a piece of software that meets the following criteria. It exposes a Web API (e.g  REST ) to a client in a single file with only a few lines of code. This file relies on a standardized Framework and set of dependencies and has no local state. Anything that fits this criteria can be run in an execution engine that provides the relevant framework and dependencies. The small amount of code then means that it can be deployed on demand. A request comes in, the code is fetched from a Repo, cached within the engine and executed. An execution engine can be multi-tenant, meaning it can be running many different micro APIs at the same time.