Die Versand-API für Deutsche Post

$client = new GuzzleHttp\Client;

$response = $client->request('POST', 'https://app.simplesell.de/api/v2/shipments', [
    'headers' => [
        'Authorization' => 'Bearer 8AUksk786f...',
        'Content-Type' => 'application/json',
    ],
    'body' => json_encode([
        'shipping_method_id' => 'df82635f-4781-4074-aba0-11df1cab2525',
        'receiver' => [
            'name' => 'SimpleSell GmbH',
            'street' => 'Im Moos',
            'house_number' => '5',
            'postal_code' => '93462',
            'city' => 'Lam',
            'country' => 'DE',
        ],
    ]),
]);

json_decode($response->getBody()->getContents());

{
    "status": "success",
    "id": "30c35bfc-da30-488b-8f65-62a8c06a1009",
    "label": "JVBERi0xLj...",
    "tracking_number": "222262010002152490",
    "tracking_url": "https://www.dhl.de/de/privatkunden/pakete-empfangen/verfolgen.html?piececode=222262010002152490",
    "return_tracking_number": null,
    "customs_document": null,
    "weight": 2.5,
    "length": 35,
    "width": 20,
    "height": 15,
    "carrier_messages": []
}