How can developers ensure consistency in character encoding between PHP scripts and external systems like DHL for seamless data transfer?

To ensure consistency in character encoding between PHP scripts and external systems like DHL for seamless data transfer, developers should use UTF-8 encoding for all data exchanged between the systems. This will help avoid issues with special characters and ensure that the data is correctly interpreted by both systems.

// Set UTF-8 encoding for PHP scripts
header('Content-Type: text/html; charset=utf-8');
mb_internal_encoding('UTF-8');

// Set UTF-8 encoding for external system communication
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, mb_convert_encoding($data, 'UTF-8'));
$response = curl_exec($curl);
curl_close($curl);