In the above video you can see a Viper Control plugin with plamonis Siri Proxy to start and stop my Viper SmartStart enabled vehicle. The command is sent from Siri to a Viper server, then relayed via cellular connection to the car. The car then broadcasts an update via RF to the key chain remote.

The Siri Proxy plugin I wrote handles interaction with a php script that runs on my web server. The php script, which I developed months ago for personal use, allows me to send commands to my car which has a Viper SmartStart module installed.

Current commands accepted are: Vehicle Arm, Vehicle Disarm, Vehicle Start, Vehicle Stop, Vehicle Pop Trunk, and Vehicle Panic. [Source]

Source [9to5mac]