App, web app or PWA: what the difference actually is

A web app is a website that behaves like a program: logging in, entering data, updating lists. You send a link and everyone can start immediately, on any device, without installation and without a shop's approval.

What a web app cannot do, or only halfway, is reach deep into the device. Background tasks that keep running, certain bluetooth devices, some forms of notifications: there the browser meets limits that differ per operating system.

For internal use — scheduling, time tracking, records, dashboards — this is nearly always the fastest and cheapest route, precisely because there is no distribution around it.

A PWA is that same web app, but installable: it gets an icon on the home screen, can work offline and in many cases can send notifications. There is still no store involved; the user puts it on their screen themselves.

On Android a PWA behaves almost like an ordinary app. On iOS support is more limited and differs per version; that is the key question to ask before building on it.

It is the cheapest way to give returning users a fixed place on their device, and often enough for a client portal, a delivery service or an internal tool.

A real app is downloaded from the App Store or Google Play and may do everything the device permits: camera, location, bluetooth, biometrics, background tasks and notifications that actually arrive. In exchange the store looks over your shoulder: every version is reviewed and rules apply, among them rules about payments.

Within that category there is another choice: one codebase for both platforms, or two separate apps in each platform's own language. The first is cheaper to build and maintain, the second gives the last few percent of performance and access to the newest a platform ships.

Rule of thumb: choose the form based on what the device has to do and how often people use it — not on what sounds modern. What is rarely used does not belong in a store but in a browser.