What is frontend?
Frontend is everything the user sees and touches — the screen part.
Difficulty 1/5
Mental model
Plain English
The frontend is the part that renders on the user's device — the buttons, forms, lists, layout, colors, animations. It runs in the browser. It cannot keep secrets and it cannot be trusted by itself.
Analogy
The frontend is the dining room of a restaurant: tables, menus, the waiter. You never enter the kitchen.
Jessica's wedding portal
The wedding dashboard, the task card, the calendar view — all frontend.
Agentify CRM
The inbox UI, the conversation pane, the contact sidebar — all frontend.
Go deeper
What you see and touch.
Common mistakes
- Putting secrets in the frontend. The user can read all of it.
- Trusting the frontend to enforce rules. It can be bypassed.
AI-agent trap
Agents often put API keys or auth checks in frontend code. Always move secrets and rules to the backend.
Quick check
Where does the frontend run?
Summary
Frontend = HTML structure + CSS styling + JavaScript behavior, running in the user's browser.
Confidence: