Fakturnaut Java SDK

Java 17+ client for the Fakturnaut API (java.net.http, Jackson): issue, validate, deliver and check EN 16931 e-invoices (XRechnung, ZUGFeRD, RO e-Factura).

<dependency>
  <groupId>com.fakturnaut</groupId>
  <artifactId>fakturnaut-sdk</artifactId>
  <version>1.0.0</version>
</dependency>

ApiClient client = new ApiClient();
String key = System.getenv("FAKTURNAUT_KEY"); // fkn_test_… for the sandbox
client.setRequestInterceptor(request -> request.header("Authorization", "Bearer " + key));
InvoicesApi invoices = new InvoicesApi(client);
InvoiceResponse issued = invoices.issueInvoice(request, Idempotency.newKey());

Errors throw ApiException; getResponseBody() is an RFC 9457 problem with a stable code.

Webhooks

boolean ok = Webhooks.verify(rawBody, request.getHeader("Einvoice-Timestamp"),
        request.getHeader("Einvoice-Signature"), System.getenv("FAKTURNAUT_WEBHOOK_SECRET"));

Generated from api/openapi.json; the helpers live in com.fakturnaut.sdk.helpers. Build and test: mvn verify.