The Microsoft Bot Builder SDK is one of three main components of the Microsoft Bot Framework. First, you have to build your bot. Your bot lives in the cloud and you host it yourself. You write it just like a web service component using Node.js or C#, like the ASP.NET Web API component. The Microsoft Bot Builder SDK is open source, so it will support more languages and web stacks over time. Your bot will have its own logic, but you also need a conversation logic using dialogs to model a conversation. The Bot Builder SDK gives you facilities for this, and there are many types of dialogs that are included, from simple yes or no questions, to full LUIS, which is one of the APIs provided by Microsoft Cognitive Services. This is what the architecture of bot looks like:
