API (Application Programming Interface) is a set of rules and protocols that defines how two software applications communicate with each other. An API acts as an intermediary between the two applications, allowing them to exchange data and functionality. For example, a weather API might allow a website to display up-to-date weather information by sending a request to the API, which then returns the relevant information to the website.
SDK (Software Development Kit) is a collection of tools and libraries that developers can use to build applications for a specific platform. An SDK typically includes pre-written code, documentation, and samples to help developers get started quickly. An SDK is usually platform-specific, meaning that different SDKs are available for different operating systems, programming languages, or devices.
In summary, an API provides a way for applications to communicate with each other, while an SDK provides the tools and libraries needed to build applications for a specific platform.