Comprehensive guide for building Progressive Web Apps (PWA) with Next.js using modern 2025 approaches. Use when users need to implement PWA features in Next.js applications including installability, offline support, service workers, web app manifests, caching strategies, push notifications, or converting existing Next.js apps to PWA. Covers both native Next.js PWA support (zero dependencies, App Router) and Serwist package (advanced offline capabilities, service worker management). Also use when troubleshooting PWA issues, optimizing PWA performance, or migrating from deprecated packages like next-pwa.