ChatBot - Easy to use chatbot platform for business
Wit.ai - Easily create text or voice based bots that humans can chat with on their preferred messaging...
Botpress - Open-source platform for developers to build high-quality digital assistants
Botsify - Ever wonder if you could replace your live chat support system with a chatbot?. Its possible now with Botsify Chatbot For Website.
Dialogflow - Conversational UX Platform. (ex API.ai)
Microsoft Bot Framework - Framework to build and connect intelligent bots.