An SDK is a collection of libraries, APIs, documentation, utilities, and/or sample code that help you implement certain features without having to do the work from scratch. SDKs vary in scope and function from implementing a feature or set of features, like an analytics SDK for instance, to building whole applications for a specific platform. Going back to our house analogy, if a library is a stove, then an SDK is a whole kitchen. While you can go and buy all your kitchen appliances, cabinets, and counters separately, it will be a lot easier to buy a full kitchen set, complete with built-in appliances and instructions on how to assemble it. SDKs can be limited in scope such as in the case with one room, but they can also have a bigger scope of a collection of rooms or even the whole house.