Web API

Web APIs are the standardized interfaces (APIs) built into web browsers, enabling client-side JavaScript to directly access and manipulate the browser's environment, device hardware, and data.

Web APIs are the core interfaces exposed by the browser, granting client-side JavaScript direct access to the host environment. This collection includes hundreds of standardized interfaces: the Fetch API, for instance, executes complex network requests, effectively replacing the older XMLHttpRequest object. Developers leverage the Geolocation API to securely access precise user coordinates (latitude and longitude), or the Web Storage API for local data persistence (e.g., localStorage). Implementing these APIs is critical for building modern, high-performance single-page applications (SPAs) that utilize native device capabilities and improve overall user experience.

https://developer.mozilla.org/en-US/docs/Web/API