Offline-First Service Worker

Client
Grant.is
Role
Frontend Engineer
Year
2025
Location
Remote
PWAPerformanceDX

Overview

Modernized the service worker to handle fingerprinted assets and surface a polite update prompt.

The Challenge

Stale caches and outdated asset paths broke offline support and confused users.

The Approach

  • Static list replaced with cache-by-prefix for /css/ and /js/.
  • Added updatefound banner wiring with SKIP_WAITING.
  • Network-aware guard to skip SW on localhost and slow connections.

The Outcome

Reliable offline behavior, clearer updates, and fewer cache-related support pings.