No specific network protocol, no standards. They can be plugged into networks like FB Messenger, Telegram, Slack and so on. Some are straight-up independent app

No specific network protocol, no standards. They can be plugged into networks like FB Messenger, Telegram, Slack and so on. Some are straight-up independent apps. In Telegram for example all you have to do is to add the chatbot like another contact. Conceptually they're not very different from IRC bots except for having natural language processing rather than simple regex/command capabilities. Chat bots are associated with text, but Google Assistant and Siri are basically chat bots plugged into voice recognition and text-to-speech interfaces.