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.