[frou_dh]

Backend does not necessarily mean web technology. I'm reminded of an oft-lost distinction between "The (Inter)net" and "The Web".

[cup-of-tea]

I've not heard of other network services using the term "backend". Is writing a mail server "back end" development?

[frou_dh]

Yes. A rather uninspiring appraisal of cyberspace — web browsing & emailing — though.