What is an app?
An app is a system that shows screens, reacts to actions, and remembers things.
Mental model
Plain English
An app is software a person opens to do something. It shows screens, it reacts when the person clicks or types, and it remembers things between sessions. Every app you use — Gmail, Notion, Instagram — fits that pattern.
An app is like a restaurant: the dining room is the screen, the kitchen is the logic, the fridge is the memory. The customer doesn't enter the kitchen; they ask the waiter.
Jessica's wedding portal shows screens (event dashboard), reacts (Add Task button), and remembers (the task list is still there tomorrow).
Agentify shows the inbox, reacts when an agent replies, and remembers every message and contact.
Go deeper
Screens + actions + memory.
Common mistakes
- Confusing 'the app' with 'the website you opened in a browser'. The app is the whole system, not just the page.
- Thinking the screen saves data. It doesn't — the backend does.
AI-agent trap
Summary
An app has three things: a user interface (what you see), logic (what happens when you act), and storage (what is remembered).