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 SDK for a mobile operating system like Android or iOS helps developers create apps that can run smoothly on those devices. By using an SDK, developers can ensure compatibility and streamline their workflow.