Olyo - Direct marketing via Facebook Messenger
Chatfuel - Chatfuel is the best bot platform for creating an AI chatbot on Facebook.
Conte.ai - Conte.ai is a modern web-service for businesses of all sizes from any industry
BotStar - BotStar | Engage Customers Online with Live Chat & Chatbots
Upcado - Super easy to use Messenger Marketing tool for your business
Telegram bot API - The Bot API allows you to easily create programs that use Telegram messages for an interface.