Command Line cURL to PHP cURL

You are passing the POST values as HTTP headers, which is not the same.

Use this:

$data = array('contact[first_name]' => 'aaaaaaa', 'api_token' => 'XXXXXXXXX');curl_setopt ($ch, CURLOPT_POST, true);curl_setopt ($ch, CURLOPT_POSTFIELDS, $data);

And remove the CURLOPT_HTTPHEADER option.

Just as a side note: the linked API description says nothing about sending login details to the API - there's only the API token (which is usual for APIs).

example :

$url = 'link_to_api';$params = array('username'=>'admin','password'=>'passw0rd');    public function call_ws_post($url = '', $params = array()){    $service_url = $url;    $curl = curl_init($service_url);    $curl_post_data = $params;    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);    curl_setopt($curl, CURLOPT_POST, true);    curl_setopt($curl, CURLOPT_POSTFIELDS, $curl_post_data);    $curl_response = curl_exec($curl);    if ($curl_response === false) {        $info = curl_getinfo($curl);        curl_close($curl);        die('error occured during curl exec. Additional info: ' . var_export($info));    }    curl_close($curl);    $decoded = json_decode($curl_response);    if (isset($decoded->response->status) && $decoded->response->status == 'ERROR') {        die('error occured: ' . $decoded->response->errormessage);    }    return $decoded;}