Can you describe how the API works at the client-server level?

API (Application Programming Interface) at the client-server level acts as an intermediary that allows the client (for example, a web application or mobile app) to request data or services from the server.

The process usually looks like this:

1. The client sends an HTTP request (GET, POST, PUT, DELETE, etc.) to the API server.
2. The server receives the request, processes it, interacts with a database or other services.
3. The server forms a response, usually in JSON or XML format, and sends it back to the client.
4. The client receives the response and uses the data to display to the user or for further logic.

For example, when requesting a list of users, the client sends a GET request to /api/users, and the server returns a JSON array with user data.

Thus, the API provides a standardized way for the client and server to interact, hiding the internal logic and structure of the server.