How to send HTTP response codes in PHP API?

In PHP, you can set HTTP response codes using the http_response_code() function. Here's how to implement it properly:

Basic Usage

<?php
// Set a 404 Not Found response
http_response_code(404);

// Set a 500 Internal Server Error response
http_response_code(500);

// Set a 201 Created response
http_response_code(201);
?>

Common HTTP Status Codes for APIs

• 200 OK - Successful GET, PUT, PATCH requests
• 201 Created - Successful POST request that creates a resource
• 204 No Content - Successful DELETE request
• 400 Bad Request - Invalid request data
• 401 Unauthorized - Authentication required
• 403 Forbidden - Access denied
• 404 Not Found - Resource not found
• 422 Unprocessable Entity - Validation errors
• 500 Internal Server Error - Server error

API Response Example

<?php
header('Content-Type: application/json');

if ($user_found) {
    http_response_code(200);
    echo json_encode(['status' => 'success', 'data' => $user]);
} else {
    http_response_code(404);
    echo json_encode(['status' => 'error', 'message' => 'User not found']);
}
?>

Note: Always set the response code before outputting any content, and consider setting appropriate headers like Content-Type for APIs.