Amazon Lex - Harness the power behind Amazon Alexa for your own conversational apps.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Landbot - An intuitive no-code conversational apps builder that combines the benefits of conversational interface with rich UI elements.
Answer Bot by Intercom - Instant resolutions, happier customers
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)