The Cache Storage API is a web API that allows developers to store and retrieve network request and response objects. It is primarily used in service workers to enable offline capabilities for web applications, ensuring that users can access content even without an internet connection. This API helps improve performance by caching resources, reducing the need for repeated network requests. With the Cache Storage API, developers can create, manage, and delete caches programmatically. It supports various methods, such as `add()`, `match()`, and `delete()`, making it easy to handle cached data. This functionality is essential for building progressive web apps (PWAs) that provide a seamless user experience.