Web API ↔ API Collection extends Browser Runtime (via window)

Source: Web APIs | MDN

DOM API

Fetch API

Web API to Data Fetch Web Resource via async Promise

Geolocation API

includes functions for interacting with Browser, system components & web services

Intersection Observer API

Picture-in-Picture API

Service Worker API

service worker as proxy between apps, browser & network - for offline support, push notifications & background sync APIs

Source: developer.mozilla.org/en

Streams API

Web API to Stream raw data over network, w/o Buffer/blob

Source: developer.mozilla.org/en

Web Storage API

Web API to persist data stored in Client across session || windows

Web Workers API

Web API to run Script in Background Thread separate Thread of main App for better perf

Source: developer.mozilla.org/en

WebRTC API

Web API to enable Web Apps to directly capture/stream media to host for live video/voice-chat & P2P file sharing

XMLHttpRequest

legacy Interface for old-school AJAX

References

1. Browser Runtime ↔ JS Runtime Environ with JS Engine, Web API, Callback Queue & Event Loop

2. Fetch API ↔ Web API to Data Fetch Web Resource via async Promise

3. MDN Web Docs ↔ FOSS wiki docs for HTML, CSS, JS & Web API

4. indexedDB ↔ Web API indexed database built into Browser with Async access

5. Web Workers API ↔ Web API to run Script in Background Thread separate Thread of main App for better perf

6. WebSockets ↔ Web API to open 2-way Client/Server connection, to push update vs Polling

7. Web Storage API ↔ Web API to persist data stored in Client across session || windows

8. Replica ↔ Local Lib to reproduce Web API functionality

9. Streams API ↔ Web API to Stream raw data over network, w/o Buffer/blob

10. WebRTC API ↔ Web API to enable Web Apps to directly capture/stream media to host for live video/voice-chat & P2P file sharing

11. useOnScreen() ↔ Custom Hook to return boolean to check if node (as ref) is visible on Viewport; Abstracts Intersection Observer API Web API