Web Storage API
The Web Storage API is a web browser API that provides mechanisms for web applications to store data locally in a user's browser. It allows for persistent storage of key-value pairs, with data surviving page reloads and browser restarts, unlike cookies which have size limitations and are sent with every HTTP request. The API includes two main storage objects: localStorage for long-term storage and sessionStorage for session-based storage that clears when the tab or window closes.
Developers should learn the Web Storage API when building web applications that need to store user preferences, authentication tokens, or application state locally without server-side storage, improving performance and user experience by reducing server requests. It's particularly useful for offline-capable apps, caching data, and maintaining state across page navigations in single-page applications (SPAs). However, it should not be used for sensitive data due to security risks, as it's accessible via JavaScript and vulnerable to XSS attacks.