Currently available as an Alexa skill to see and listen, but it doesn't let you talk to the person at the door. It seems that on Echo Show you can say "Answer the front door" for two way communication, but the Portal says "That feature is not supported". Only "show me the front door" is supported. It would be better to have a native Portal application because I have an Alexa in the room with better speakers, so I would rather leave Alexa disabled on my Portal and would like to say "Hey Portal answer the front door".