Scalability
Vertical scaling
Vertical scaling doesn't have any meaningul differences from the description provided in the Monolith section.
Horizontal scaling
Horizontally scaling microservices should be an easy operation to perform, potentially automated by an external orchestrator, such as Kubernetes.
One of the driving principles for microservices apart from loosely coupled services is to be able to adapt and react to change faster, horizontally scaling a given service in a fast way is crucial for our microservice architecture to be flexible so it can properly absorb traffic spikes.