VISEO Bot Maker - Create chatbots and vocal apps in just a few clicks
Dialogflow - Conversational UX Platform. (ex API.ai)
boteria - Business chatbot has never been so simple and fast
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Botpress - Open-source platform for developers to build high-quality digital assistants
Botkit - Botkit is an open source developer tool for building chat bots, apps and custom integrations for major messaging platforms.