Frontend and backend
Level 1
The frontend is what the user sees; the backend is the part that runs on servers.
Term 1 of 6 in Building AI systems
In plain language
Buttons, text and layout are frontend. Storing data, checking passwords and calling AI models are backend. Anything secret has to live in the backend.
Think of it like this
The dining room and the kitchen.
Why it matters
AI keys and business rules belong in the backend. Putting them in the frontend is the classic beginner security mistake.