What is a Service?

https://en.m.wikipedia.org/wiki/Server_(computing)

Server client vs peer to peer

Within web based services, this often means features that can be accessed by creating a user account.  For some services, there are a single user, whereas others low for true multiuser environment.

Integration with Authelia, reverse proxy.

In relation to SaaS

https://en.m.wikipedia.org/wiki/Software_as_a_service