This chapter was the conclusion of our journey from an initial echo example up to a realistic application being deployed on a cloud environment, which was scalable and secured with TLS.

Reverse proxies are some of the basic tools needed to deploy applications, especially when they are composed of several services. Reverse proxies that operate on layer 7 also often implement load balancing features. Load balancing allows us to distribute the load between several instances of a service. Some of these tools, such as Traefik, leverage the Docker ecosystem to make their configuration very easy and dynamic.

Docker Compose allows us to manage containers much more easily than directly using Docker. Using it simplifies the deployment of applications that use multiple containers. Moreover, it allows us to easily scale a container up or down by starting or stopping some instances very easily.

Let's Encrypt is a great tool for two main reasons: it is one of the only solutions providing valid certificates for free, and it allows us to fully automate the renewal of these certificates. So, this service solves two of the main issues that prevent many small websites and companies from protecting their traffic with TLS.

The next chapter will explore how to extend reactive programming and observables beyond a single process or application. It will propose ways to use observables to communicate between processes and systems, is an attempt to go a step further towards reactive systems.