Can you include raw JSON in Guzzle POST Body?

You can send a regular array as JSON via the 'json' request option; this will also automatically set the right headers:

$headers = [    'NETOAPI_KEY' => env('NETO_API_KEY'),    'Accept' => 'application/json',    'NETOAPI_ACTION' => 'GetOrder'];$GetOrder = [    'Filter' => [        'OrderID' => 'N10139',        'OutputSelector' => ['OrderStatus'],    ],];$client = new client();$res = $client->post(env('NETO_API_URL'), [    'headers' => $headers,     'json' => $GetOrder,]);

Guzzle 7 Here

The below worked for me with raw json input

    $data = array(       'customer' => '89090',       'username' => 'app',       'password' => 'pwd'      );    $url = "http://someendpoint/API/Login";    $client = new \GuzzleHttp\Client();    $response = $client->post($url, [        'headers' => ['Content-Type' => 'application/json', 'Accept' => 'application/json'],        'body'    => json_encode($data)    ]);             print_r(json_decode($response->getBody(), true));

For some reasons until I used the json_decode on the response, the output wasn't formatted.

You probably need to set the body mime type. This can be done easily using the setBody() method.

$request = $client->post(env('NETO_API_URL'), ['headers' => $headers]);$request->setBody($GetOrder, 'application/json');