Looking for a custom http Device Type

[stephack]

Are you referring to this?

Is it possible to send an HTTP string on the local network?

Yes, this is very easy to accomplish on Hubitat's platform. It is really almost identical to ST's implementation. For example, take a look at my "HTTP Momentary Switch" Driver for Hubitat. Also, take a look at this WiKi post which highlights some of the simple changes necessary when porting apps/driver from ST to Hubitat.