Phone, Desktop, and Web Apps

Lesson 6 · taught by Pip

Hello again, friend. Pip here, lamp lit and steady. 🐙

Way back in lesson one I mentioned apps come in three everyday flavors. Now that you know the front end, the back end, and where data lives, let's meet those three properly. The good news: it's the same restaurant all along. What changes is only the door you walk through to reach it.

Three doorways to the same restaurant

Picture one restaurant with three entrances — same kitchen, same menu, just a different way in.

A phone app is the door you install. You go to a store (the App Store or Google Play), download it, and an icon lives on your phone afterward. Like keeping a favorite restaurant's takeout containers in your cupboard — a piece of it now sits at home, ready when you tap.

A desktop app is the same idea on a laptop or computer. You install a program — a photo editor, a word processor — and it lives on that machine. The same cupboard, with more room to work.

A web app is the door with no install at all. You open a browser (Chrome, Safari) and visit an address, like online email or a banking page. Nothing gets kept on your device — it's like walking up to the restaurant itself each time. Nothing to store, but you do make the trip.

Same instructions, same storage, same friendly face.

The trade-offs, in plain terms

Each doorway gives you something and asks something in return.

Installed apps (phone and desktop) put a piece of the app right on your device. That brings two gifts. First, speed and offline use: part of it is already there, so it can often work without a connection — like reading a note you saved earlier. Second, it can reach things on your device, like the camera or notifications. The cost: you have to install it, it takes up space, and updates download now and then.

Web apps ask nothing of your device — no install, no space, no update chore — and you always get the newest version simply by visiting. That's the gift: instant access, anywhere, on any browser. The cost: you usually need to be online, because the real work waits across the connection, in the kitchen we talked about.

So it's a gentle tug-of-war: keep a piece at home (fast, works offline, but you install and update) versus visit fresh each time (nothing to install, always current, but you need a connection).

Why one app often serves all three

Here's the clever part. Building three separate apps is a lot of work — three kitchens to keep in sync. So many companies build one kitchen, then put three doors on it.

Remember that the front end and back end talk by passing messages. That's the secret. The back end — the part that does the work — doesn't care which door your request came through. A phone, a desktop program, and a browser can all send the same request to the same kitchen and get the same answer.

So a company writes the hard part once, then dresses it up as a phone app, a desktop app, and a web page. To you it feels like three products. Underneath, it's mostly one — quietly serving every doorway.

Your turn

Pick one service you use through more than one doorway — email is a great example, opened as a phone app and as a web page in a browser.

Now ask: is your information the same in both? If a message you read on your phone shows up already-read in the browser, you've just spotted one shared kitchen feeding two different doors.

Next, we open the doors. In How a Finished App Reaches You, we'll follow a built app the last mile — onto a server, into an app store, and finally into your hands. 🐙