You can store and retrieve information at different scopes using Attributes in the SDK. Attributes allow you to keep track of what happened so far, and to use this information to determine what happens next. You can define attributes that for a single request, for a single customer session, or for the lifetime of your skill.
You can deliver responses to your customers that include text-to-speech, audio and video streams, and cards and other visual elements. Customers will receive one or more of these elements depending on what Alexa-compatible device they are using. Using the SDK, you can build responses that include all of these elements.