Chatfuel - Chatfuel is the best bot platform for creating an AI chatbot on Facebook.

nlp_compromise - NLP tool for understanding, changing & playing w/ english.

Botsify - Ever wonder if you could replace your live chat support system with a chatbot?. Its possible now with Botsify Chatbot For Website.

JAICP - JAICP (Just AI Conversational Platform) is a full-fledged conversational platform: scalable, NLP-powered, and secured. Build chatbots, voice assistants, smart devices in the snap of a finger

ManyChat - ManyChat lets you create a Facebook Messenger bot for marketing, sales and support.

Facebook DeepText - Facebook's text understanding engine