PWA on iOS, Part 2: HTTPS, Manifest and Service Worker

This is Part 2 of the PWA on iOS series, and it’s the most practical one. There will be almost no history or corporate politics here, but there is groundwork you need for the rest of the series to make sense. You’ll learn why a PWA works on a laptop but not on an iPhone, and how HTTPS, the manifest, the Service Worker lifecycle, and two caches decide that.

The typical story starts at a desk. The frontend runs on a laptop, the phone is on the same Wi-Fi network, Safari on the iPhone has an address like http://192.168.1.20:5173 open, and everything looks fine: the interface loads, the buttons work, and our PWA's icon sits next to the others on the phone's Home Screen. Then someone turns on airplane mode, taps the icon, and instead of the app, sees a message saying the page can't be opened. Meanwhile, everything is green in Chrome on the laptop: the worker is registered, the cache is full, and the team spends the first half hour hunting for a bug in the manifest, even though the phone has never seen that worker.