Chatfuel - Chatfuel is the best bot platform for creating an AI chatbot on Facebook.
Dialogflow - Conversational UX Platform. (ex API.ai)
Landbot - An intuitive no-code conversational apps builder that combines the benefits of conversational interface with rich UI elements.
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Botsify - Ever wonder if you could replace your live chat support system with a chatbot?. Its possible now with Botsify Chatbot For Website.
Botpress - Open-source platform for developers to build high-quality digital assistants