API

You might say

My website needs data from the backend. People keep saying I need an API—what is that?

An agreed way for two pieces of software to request and return informationFor example, a weather app can ask a weather service for today's Shenzhen forecast and receive the temperature and conditions. The API defines where the request goes, what it carries, and what comes back; it is not the page, backend code, or database.

Know first

HTTP

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 save

FrontendRead the input and show a pending state

Quick checkChoose the best answer

Saving produces no result. How do you first check whether the API is involved?

You can say this to an AI Agent

Saving produces no result. Inspect the API URL, method, submitted data, status, response body, and how the page handles it. Fix the cause, save again, confirm the response matches the contract and the page shows the right result; if it persists data, refresh to confirm it remains.