What is meant by passing parameters in the request body?

Passing parameters in the request body means that the data required to process the request is sent not in the URL (as query string parameters), but inside the HTTP request itself.

This is typically used for POST, PUT, PATCH requests, where complex data structures (such as JSON, XML) or large volumes of information need to be transmitted.

For example, when submitting a user registration form, the data (name, email, password) is placed in the request body in JSON format:

{
  "username": "user123",
  "email": "user@example.com",
  "password": "securepass"
}

This approach allows transmitting more structured and voluminous data than through URL parameters and provides greater security, as the request body is not visible in the browser's address bar.