between services in the cluster and from a service to external
   services. The proxies form a _secure microservice mesh_ providing a rich
   set of functions like discovery, rich layer-7 routing, circuit breakers,
   policy enforcement and telemetry recording/reporting
   functions.

  > Note: The service mesh is not an overlay network. It
  > simplifies and enhances how microservices in an application talk to each

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Recap

In summary, you declare **once** the types of parameters, body, etc. as function parameters.

You do that with standard modern Python types.

You don't have to learn a new syntax, the methods or classes of a specific library, etc.

Just standard **Python 3.8+**.