Frontend vs Backend
The two halves of every app
⏱ Est. ~4 min
01 · Read
Most software is split into two halves: frontend and backend.
Frontend is everything you see and interact with — buttons, menus, animations, text, images. It runs in your browser or on your phone.
Backend is everything that happens behind the scenes — verifying passwords, processing payments, querying databases, sending emails. It runs on a server somewhere.
Think of a restaurant: the frontend is the dining area (where guests sit, look at menus, and eat), and the backend is the kitchen (where food gets prepared, orders get managed, inventory gets tracked). Guests never see the kitchen, but all the real work happens there.
Key points
- Frontend = what users see and interact with (HTML, CSS, JavaScript)
- Backend = the logic and data processing users don't see (server, database, API)
- The two sides constantly talk to each other — frontend sends requests, backend sends responses
- Some engineers specialize in one side; "full-stack" engineers do both
02 · Drag to sort
Drag each item to the right half of the app. Does it belong to the Frontend or the Backend?
(This section is interactive — please enable JavaScript.)
03 · Match
Match each example to the part of the app that handles it.
(This section is interactive — please enable JavaScript.)
04 · Quiz
When you type your password and click "log in", where is your password actually verified?
- In your browser (frontend)
- In the address bar
- On the server (backend)
- In your phone's operating system
Other lessons in this chapter
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