Frontend

You might say

People keep talking about the frontend and backend. What's the difference?

The layer people directly see, click, and type intoOn a sign-up page, the fields, submit button, and pending, success, or error messages belong to the frontend; whether the account was actually created must come from the backend result.

Which parts handle one save?

Highlighted steps show what this term is responsible for in the flow.

Frontend · Browser

API · Contract

API/api/profile

URL · method · body

—response

status · body

Backend

Waiting for request

Signed-in user?
Name length OK?
Allowed to update?
Write only after checks

Database

profilestable

id	name	updated
7	Momo	yesterday

1 / 6Edit and saveFocus

FrontendRead the input and show a pending state

Quick checkChoose the best answer

The page says Saved, but the old value returns after refresh. What should you check first?

You can say this to an AI Agent

The page says Saved, but the value disappears after refresh. Check whether the frontend reports success too early and whether it handles the save request and refresh read correctly. Fix the cause, then save and refresh again to verify it.