$ch = curl_init();

$headers  = [

            'x-api-key: XXXXXX',

            'Content-Type: text/plain'

        ];

$postData = [

    'data1' => 'value1',

    'data2' => 'value2'

];

curl_setopt($ch, CURLOPT_URL,"XXXXXX");

curl_setopt($ch, CURLOPT_POST, 1);

curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($postData));           

curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

$result     = curl_exec ($ch);

$statusCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);