Answer

What is the difference between a PWA and a regular website?

Short answer

Technically, a PWA is just a regular website that additionally serves over HTTPS, links a Web App Manifest, and registers a service worker. Nothing about the HTML, CSS or JS changes — the difference is entirely in those three additions, which unlock installability, offline caching and push notifications.

By InstantPWA engineering·Reviewed July 25, 2026

What stays the same

Your routing, content, backend and SEO fundamentals are identical to a normal website — a PWA is not a different tech stack.

What is added

A manifest.webmanifest file, a service-worker script registered on load, and HTTPS (required by browsers for service workers).

What you gain

Home-screen install, offline caching, background sync, web push and (on Chromium) app shortcuts and window controls overlay.

Sources

web.dev — What are Progressive Web Apps?

Related

A PWA (Progressive Web App) is a regular website that meets three technical criteria — HTTPS, a Web App Manifest and a service worker — so browsers let visitors install it on their home screen. Once installed, it launches like a native app, works offline and can send push notifications.

PWA vs native app: what does each cost?

Building a PWA typically costs 30-50% of an equivalent native iOS + Android app because you ship one codebase to three platforms (iOS, Android, desktop). Maintenance is roughly one-fifth: no app-store review, no separate release trains, no platform-version fragmentation.

How do you test a PWA with Lighthouse?

Open Chrome DevTools, go to the Lighthouse panel, select the categories you want (Performance, PWA-related checks live under "Best Practices" in modern Lighthouse) and click "Analyze page load". Lighthouse reports whether your manifest is valid, whether a service worker is registered, and whether the page is served over HTTPS.

What is Workbox?

Workbox is a collection of open-source JavaScript libraries, maintained by Google, that wraps common service-worker patterns — precaching, runtime caching strategies, background sync, expiration — behind a simple API, so developers do not have to hand-write low-level Cache Storage and fetch-event logic.

What icon sizes does a PWA need?

A PWA manifest needs at least a 192x192 and a 512x512 icon to be installable on Chromium browsers. For best results across platforms, also include a maskable icon (so Android does not crop your logo oddly) and a separate 180x180 apple-touch-icon link for iOS Safari, which does not read the manifest for its home-screen icon.