Progressive Web Apps combine web and native app capabilities, delivering app-like experiences through browser technologies. Built on service workers, web app manifests, and HTTPS, PWAs work offline, install to home screens, and send push notifications — all without app store gatekeeping. The critical insight: PWAs don't replace websites or native apps; they bridge the gap by giving web content the reach of URLs and the engagement of apps, with 68% lower development costs than maintaining separate iOS and Android codebases.
What This Cheat Sheet Covers
This topic spans 20 focused tables and 122 indexed concepts. Below is a complete table-by-table outline of this topic, spanning foundational concepts through advanced details.
Table 1: Core RequirementsTable 2: Web App Manifest PropertiesTable 3: Service Worker LifecycleTable 4: Caching StrategiesTable 5: Cache API OperationsTable 6: Offline Data StorageTable 7: Installation & PromotionTable 8: Push NotificationsTable 9: Background OperationsTable 10: App Shell ArchitectureTable 11: Advanced Manifest FeaturesTable 12: Display Modes & UI CustomizationTable 13: Platform-Specific FeaturesTable 14: Performance OptimizationTable 15: Testing & DebuggingTable 16: Security ConsiderationsTable 17: Browser Compatibility (2026)Table 18: Workbox Library (Google)Table 19: Common Pitfalls & SolutionsTable 20: iOS-Specific Considerations
Table 1: Core Requirements
| Requirement | Example | Description |
|---|---|---|
https://example.com | • Mandatory for service workers and most PWA APIs • localhost/127.0.0.1 exempt for development • prevents man-in-the-middle attacks on cached assets. | |
<link rel="manifest" href="/manifest.json"> | • JSON file defining app name, icons, display mode • linked from HTML • enables installation prompt and appearance customization. | |
navigator.serviceWorker.register('/sw.js') | • JavaScript proxy between web app and network • enables offline functionality, push notifications, and background sync • runs independently of page. |