Write request and receive a response with web chat bot

I'm trying to create simple interface to analyze conversation with different available web chatter bots. So I have no idea in which direction I've to research, if only thing I want is a write massage to the chatterbot for example cleverbot.com from the textbox of my application and get answer string from it. if I can figure it out with this, then I want get the list of available web chat bots to choose. Maybe I can use WebClient for this goal, need any advice on this direction