$url = '';
$postFields = array(
'apiOperation' => 'CREATE_CHECKOUT_SESSION',
'order' => array(
'currency' => '',
'id' => ''
),
'interaction' => array(
'returnUrl' => ''
)
);
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_HTTPHEADER, array(
'Content-Type: application/json'
));
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, json_encode($postFields));
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, true);
$output = curl_exec($curl);
curl_close($curl);