Types of Apps
The word “app” covers several very different shapes — a page in a browser, an icon on a phone, a command in a terminal. Pick the shape that fits the goal before you build, and everything after gets easier.
Five Shapes
Almost every product is one of these — or a combination of them.
- Web app — runs in a browser, nothing to install
- Mobile app — iOS or Android, installed on the phone
- Desktop app — installed on a computer
- CLI tool — runs in a terminal
- Service / API — no UI; other programs call it
Reach vs. Capability vs. Effort
No shape wins on everything. Each trades reach, device capability, and build effort differently.
- Web — easiest to share; just send a link
- Mobile — best device access, but app-store friction
- CLI — fast to build, for a developer audience
- Service — a backend other apps build on
Which One Fits?
Match the shape to who uses it and where. The same idea points at a different shape depending on the answer.
Something you share by link → a web app.
Most Products Combine Shapes
Real products rarely pick just one. A single product often stacks several shapes, each doing the job it is best at.
Build It
How to implement: for the tool you want to build, write down the one shape that fits best — and why: who uses it, and on what device.
- Weekly AI Tasks tracker — a web app for the task UI, plus a service that receives WhatsApp / messaging webhooks. That combination is deliberate.
- Personal brand site — a web app, and specifically a static site (no server needed), which is the cheapest to host and share.
What you learned
“App” is five shapes — web, mobile, desktop, CLI, service — each trading reach, capability, and effort. Match the shape to who uses it and where, and remember most real products combine several.