PWA explained: what a progressive web app adds to an ordinary web app
A progressive web app, or PWA, is a mobile web app that adds an installable identity: a manifest file and a service worker let it be added to the home screen, launch without browser chrome, cache its own files for offline use, and on supported platforms receive push notifications.
It is the same web app underneath. Nothing about the PWA label grants a page new access to the phone's hardware, and that is the single most common misreading of the term.
What makes a web app "progressive"?
- A web app manifest. A small JSON file naming the app, its icons and its display mode. Setting display to standalone or fullscreen is what makes the launched app look like an app rather than a browser tab.
- A service worker. A script sitting between the app and the network, caching files and responses so the app opens without a connection and survives a bad signal in a basement plant room.
- HTTPS. Service workers and camera access both require a secure context. There is no production shortcut around it.
"Progressive" is a claim about graceful degradation: the same URL should work as an ordinary page for anyone whose browser supports none of the above, and quietly gain the extras for anyone whose browser does.
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How does a PWA get installed?
Installation is a browser action, not an app store transaction. On Android, Chrome can offer an install prompt of its own accord, and the installed result sits in the launcher and the task switcher much like a native app. On iOS, the person has to open the share sheet and tap Add to Home Screen, and nothing in the page can trigger that for them.
Which means iOS install rates stay low unless the interface tells people, in words, exactly which two taps to make. Product teams routinely budget for the install and get very little of it.
How PWA support differs between iOS and Android
The gap is narrower than it was and still real. Apple's WebKit team announced Web Push for Home Screen web apps in iOS and iPadOS 16.4: a web app can ask for notification permission, but only after it has been added to the Home Screen, only if its manifest sets display to standalone or fullscreen, and only in response to a direct user action such as tapping a subscribe button. On Android, a web app can request notification permission without being installed at all.
Storage is the other difference worth knowing about. Browsers evict cached data belonging to sites the user has not returned to, and iOS is the more aggressive of the two, so a PWA someone opens once a quarter may find its cache empty every single time.
The hardware ceiling does not move either. A PWA on an iPhone still has no ImageCapture API, which per the compatibility data on caniuse.com is unsupported in every Safari version on macOS and iOS, so torch and focus control stay out of reach whether the app is installed or not.
PWA example: a recurring site inspection tool
A facilities team gives its contractors a PWA. Installed once, it sits on the home screen, opens with no connection in a plant room, queues captures locally, and uploads when the signal returns. The Android contractors get a notification when a job is assigned. The iPhone contractors get one too, but only the ones who added it to the Home Screen.
That split is the honest shape of a PWA rollout. Plan for it in week one instead of discovering it in week three.
When a PWA is the wrong answer
- One time users. If someone will use it once, asking them to install anything is friction with no return. A plain mobile web app at a link is the right shape.
- Hardware dependent work. Background recording, Bluetooth peripherals, deep camera control. These are native requirements and a manifest file does not change that.
- Notification dependent products. If the product only functions when a push arrives, the iOS install requirement is a structural problem rather than a conversion one.
- Anything needing app store distribution. Procurement teams and IT departments that manage devices through an MDM often cannot deploy a PWA the way they deploy an app.
What PWA is confused with
A PWA is not a hybrid app. A hybrid app is a native shell wrapping web content, shipped through the app store, and it does get native APIs through a bridge. A PWA has no shell and no bridge. Both get called "a web app in an app" in procurement documents, and the difference decides what the camera can do.
For customer facing capture, the calculation usually lands the other way entirely. Venta Capture, a product of VentaVid, runs guided capture in the mobile browser with no app and no account, because the participant is typically whoever is already standing at the vehicle or the property and will do it once. Installing anything, a PWA included, would cost more completed submissions than it would buy.
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