A Software Development Kit (SDK) is a collection of tools, libraries, and documentation that developers use to create applications for specific platforms or frameworks. SDKs simplify the development process by providing pre-built functions and components, allowing developers to focus on building unique features rather than starting from scratch. Typically, an SDK includes application programming interfaces (APIs), code samples, and debugging tools. For example, an Android SDK helps developers create apps for Android devices, while an iOS SDK is designed for Apple products. By using an SDK, developers can ensure their applications are compatible and optimized for the intended platform.