clueless question! - sortof sms/text related

[bruce]

Hi guys.

This is totally off topic -- so delete as required!!

I'm investigating a project, and have no clue as to where to start, other
than Google/reseach/etc..

Curious as to how to setup a test system to have test users send/receive
sms/test messages.

If a user has a mobile/app that connects back to the "server" for the msg
handling "stuff" does the process need to involve a twillo/telcom?

I've seen open source projects (zulip) that have the server/client/mobile
parts, but have no clue as to what's involved with architecting or building
out a complete/working solution.

So, I figured I'd ask here if anyone has any insight into this kind of
system, or has pointers to any company/resource that I could talk to.

Thanks guys -- Have a cool weekend!