Service Workers
Service Workers power offline support, background sync, and push notifications. Required for serious PWA/installable app behavior.
What It Defines
Defines the Service Worker API: background JS scripts that intercept network requests, manage caches, and enable offline-first web apps. The foundation of Progressive Web Apps.
Canonical (Normative)
Convenient (Practical)
Publishes web platform specs including CSS, accessibility, security policies, Service Workers, Web App Manifest, and many browser APIs. Also maintains some versioned HTML/DOM specs.
Related Specs
Required for Add to Home Screen / Install App functionality on iOS and Android. Defines how your web app presents when installed as a native-like app.
The spec behind every HTML page, form, and browser API. The canonical reference for how browsers actually parse and process HTML.
Required for web push notifications — the re-engagement channel for PWAs. Works with Service Workers and the Notifications API. Understanding VAPID and the subscription lifecycle prevents broken push implementations.
Streams are how modern browsers handle large data: fetch response bodies, file reads, compression, and encoding are all stream-based. Understanding backpressure and piping is essential for efficient data processing.