E-Rechnungen, die jede Prüfung bestehen. Per API.

# sellerId: ID Ihres Verkäufers aus dem Portal
curl -X POST https://api.fakturnaut.com/v1/invoices \
  -H "Authorization: Bearer $FAKTURNAUT_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen 2>/dev/null || cat /proc/sys/kernel/random/uuid)" \
  --data @- <<'JSON'
{
  "sellerId": "5b1d7f0e-3c2a-4e8b-9f61-2d4c8a7e9b03",
  "number": "RE-2026-0042",
  "issueDate": "2026-11-02",
  "dueDate": "2026-12-02",
  "buyerReference": "PO-4711",
  "buyer": {
    "name": "Muster GmbH",
    "electronicAddress": "rechnung@muster-gmbh.example",
    "electronicAddressScheme": "EM",
    "address": {
      "street": "Musterstraße 1",
      "city": "Berlin",
      "postCode": "10115",
      "country": "DE"
    }
  },
  "lines": [
    {
      "name": "Softwarelizenz November",
      "quantity": 1,
      "unitCode": "C62",
      "netPrice": 490,
      "vatRate": 19
    },
    {
      "name": "Einrichtung",
      "quantity": 4,
      "unitCode": "HUR",
      "netPrice": 95,
      "vatRate": 19
    }
  ]
}
JSON

// sellerId: ID Ihres Verkäufers aus dem Portal
const invoice = {
  "sellerId": "5b1d7f0e-3c2a-4e8b-9f61-2d4c8a7e9b03",
  "number": "RE-2026-0042",
  "issueDate": "2026-11-02",
  "dueDate": "2026-12-02",
  "buyerReference": "PO-4711",
  "buyer": {
    "name": "Muster GmbH",
    "electronicAddress": "rechnung@muster-gmbh.example",
    "electronicAddressScheme": "EM",
    "address": {
      "street": "Musterstraße 1",
      "city": "Berlin",
      "postCode": "10115",
      "country": "DE"
    }
  },
  "lines": [
    {
      "name": "Softwarelizenz November",
      "quantity": 1,
      "unitCode": "C62",
      "netPrice": 490,
      "vatRate": 19
    },
    {
      "name": "Einrichtung",
      "quantity": 4,
      "unitCode": "HUR",
      "netPrice": 95,
      "vatRate": 19
    }
  ]
};

const response = await fetch('https://api.fakturnaut.com/v1/invoices', {
  method: 'POST',
  headers: {
    Authorization: `Bearer ${process.env.FAKTURNAUT_KEY}`, // fkn_test_…
    'Content-Type': 'application/json',
    'Idempotency-Key': crypto.randomUUID(),
  },
  body: JSON.stringify(invoice),
});
const issued = await response.json();

<?php
// sellerId: ID Ihres Verkäufers aus dem Portal
$invoice = <<<'JSON'
{
  "sellerId": "5b1d7f0e-3c2a-4e8b-9f61-2d4c8a7e9b03",
  "number": "RE-2026-0042",
  "issueDate": "2026-11-02",
  "dueDate": "2026-12-02",
  "buyerReference": "PO-4711",
  "buyer": {
    "name": "Muster GmbH",
    "electronicAddress": "rechnung@muster-gmbh.example",
    "electronicAddressScheme": "EM",
    "address": {
      "street": "Musterstraße 1",
      "city": "Berlin",
      "postCode": "10115",
      "country": "DE"
    }
  },
  "lines": [
    {
      "name": "Softwarelizenz November",
      "quantity": 1,
      "unitCode": "C62",
      "netPrice": 490,
      "vatRate": 19
    },
    {
      "name": "Einrichtung",
      "quantity": 4,
      "unitCode": "HUR",
      "netPrice": 95,
      "vatRate": 19
    }
  ]
}
JSON;

$ch = curl_init('https://api.fakturnaut.com/v1/invoices');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer ' . getenv('FAKTURNAUT_KEY'), // fkn_test_…
        'Content-Type: application/json',
        'Idempotency-Key: ' . bin2hex(random_bytes(16)),
    ],
    CURLOPT_POSTFIELDS => $invoice,
]);
$issued = json_decode(curl_exec($ch), true);

// sellerId: ID Ihres Verkäufers aus dem Portal
String invoice = """
    {
      "sellerId": "5b1d7f0e-3c2a-4e8b-9f61-2d4c8a7e9b03",
      "number": "RE-2026-0042",
      "issueDate": "2026-11-02",
      "dueDate": "2026-12-02",
      "buyerReference": "PO-4711",
      "buyer": {
        "name": "Muster GmbH",
        "electronicAddress": "rechnung@muster-gmbh.example",
        "electronicAddressScheme": "EM",
        "address": {
          "street": "Musterstraße 1",
          "city": "Berlin",
          "postCode": "10115",
          "country": "DE"
        }
      },
      "lines": [
        {
          "name": "Softwarelizenz November",
          "quantity": 1,
          "unitCode": "C62",
          "netPrice": 490,
          "vatRate": 19
        },
        {
          "name": "Einrichtung",
          "quantity": 4,
          "unitCode": "HUR",
          "netPrice": 95,
          "vatRate": 19
        }
      ]
    }
    """;

HttpRequest request = HttpRequest.newBuilder(URI.create("https://api.fakturnaut.com/v1/invoices"))
    .header("Authorization", "Bearer " + System.getenv("FAKTURNAUT_KEY")) // fkn_test_…
    .header("Content-Type", "application/json")
    .header("Idempotency-Key", UUID.randomUUID().toString())
    .POST(HttpRequest.BodyPublishers.ofString(invoice))
    .build();
HttpResponse<String> issued = HttpClient.newHttpClient()
    .send(request, HttpResponse.BodyHandlers.ofString());

// sellerId: ID Ihres Verkäufers aus dem Portal
var invoice = """
    {
      "sellerId": "5b1d7f0e-3c2a-4e8b-9f61-2d4c8a7e9b03",
      "number": "RE-2026-0042",
      "issueDate": "2026-11-02",
      "dueDate": "2026-12-02",
      "buyerReference": "PO-4711",
      "buyer": {
        "name": "Muster GmbH",
        "electronicAddress": "rechnung@muster-gmbh.example",
        "electronicAddressScheme": "EM",
        "address": {
          "street": "Musterstraße 1",
          "city": "Berlin",
          "postCode": "10115",
          "country": "DE"
        }
      },
      "lines": [
        {
          "name": "Softwarelizenz November",
          "quantity": 1,
          "unitCode": "C62",
          "netPrice": 490,
          "vatRate": 19
        },
        {
          "name": "Einrichtung",
          "quantity": 4,
          "unitCode": "HUR",
          "netPrice": 95,
          "vatRate": 19
        }
      ]
    }
    """;

using var request = new HttpRequestMessage(HttpMethod.Post, "https://api.fakturnaut.com/v1/invoices")
{
    Content = new StringContent(invoice, Encoding.UTF8, "application/json"),
};
request.Headers.Authorization = new AuthenticationHeaderValue(
    "Bearer", Environment.GetEnvironmentVariable("FAKTURNAUT_KEY")); // fkn_test_…
// A new key per invoice; reuse it only when you retry this request.
request.Headers.Add("Idempotency-Key", Guid.NewGuid().ToString());
var issued = await http.SendAsync(request); // http: your shared HttpClient