Is it possible to add non-snmp devices?

Say I need to monitor a specific website for uptime but don't have snmp level access. I looked up the services check however from what I understand it still relies on the device being added the usual way which requires snmp.

Assuming I can't add non-snmp devices, could someone point me in the right direction on extending Observium to add this functionality?

Ultimately, I want 4 monitors: ping, tcp protocol checks (custom ports), http(s) (simple or with response analysis) and ssh. If I can do that, then graphing the results will be trivial.

I realize there are other tools that have these features but I prefer the Observium interface.

Cheers,

Cory