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Frontend Development › Rendering Strategies

Progressive Web App

A web app that can be installed and used offline like a native one.

Frontend Engineer · Mid-level

Also known as: progressive web app, pwa, installable web app

A Progressive Web App (PWA) is a website with app capabilities: installable (manifest with icons, name, display mode), offline-capable (service worker caching shell and data), and re-engageable (push notifications) — served over HTTPS with a registered worker meeting the installability criteria.

manifest (identity) + service worker (offline) + HTTPS → installable, resilient

Installation adds a home-screen icon and standalone window without app stores; offline-first caching makes flaky networks survivable; push re-engages. Capabilities (file handling, sharing, device APIs) keep expanding the “progressive” envelope toward native parity.

The classic mistakes:

  • Manifest-only “PWA.” An install prompt with no offline story installs a bookmark that fails without network. Offline function is the substance; installability is packaging.
  • Caching without strategy. Precaching everything bloats installs; caching nothing fails offline. Shell + runtime data with versioned invalidation (see service worker).
  • Ignoring iOS gaps. Platform support differs (installation flows, push, background capabilities) — test the actual devices, design fallbacks, track convergence.
  • App-store thinking. PWAs update on deploy (no review lag) but discover through the web (no store placement). Distribution and update models differ — plan both.
  • Permission spam. Prompting notifications and installation on first paint burns trust. Earn placement: value first, prompts at meaningful moments.
  • Offline as error page. A network-error fallback isn’t an offline experience. Design cached content, queued actions and sync states as features.
  • Assuming native parity. Hardware, background execution and OS integration still favour native for demanding cases. Choose PWA where web strengths (reach, linkability, instant updates) dominate.

When to build one: reach-first apps needing resilience and re-engagement without store friction. Manifest, worker, offline design, honest capability assessment — the web, progressively app-shaped.