What does the server return if a request to it is successful?

If a request to the server is successful, the server usually returns an HTTP response with a status code in the range of 200–299. The most common code is 200 OK.

The response contains:

• Status code (e.g., 200).
• Response headers (Content-Type, Content-Length, etc.).
• Response body with the requested data (HTML, JSON, file, etc.).

For example, a successful GET request to an API server will return:

HTTP/1.1 200 OK
Content-Type: application/json

{"id":1,"name":"Example"}

Thus, a successful response means that the server processed the request without errors and returns the expected data.