Web APIs

Web APIs are standardized JavaScript interfaces that expose browser functionality, device hardware, and network capabilities to client-side code, driving modern application architecture.

Web APIs are the essential interfaces connecting client-side JavaScript to the operating environment and external resources. These APIs abstract complex operations into predictable methods: for instance, the Fetch API manages asynchronous network requests (GET, POST), typically exchanging data in JSON format. The Document Object Model (DOM) API is fundamental, providing structure and manipulation methods for HTML documents. Developers utilize hundreds of these specifications—including the Geolocation API for device location or the Web Storage API for local data persistence—to build rich, high-performance web applications that rival native desktop experiences.

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