diff --git a/backend/src/main/java/de/assecutor/votianlt/service/PdfToolService.java b/backend/src/main/java/de/assecutor/votianlt/service/PdfToolService.java
index b24cfbf..a88c8bf 100644
--- a/backend/src/main/java/de/assecutor/votianlt/service/PdfToolService.java
+++ b/backend/src/main/java/de/assecutor/votianlt/service/PdfToolService.java
@@ -19,7 +19,8 @@ import java.util.List;
 
 /**
  * Client for the external PDF Tool (ZUGFeRD converter). Sends an invoice PDF
- * together with the structured invoice data to {@code POST /api/invoices/sign}
+ * together with the structured invoice data to {@code POST /invoices/sign}
+ * (relative to the configured base URL, e.g. http://localhost:8084/api/v1)
  * and receives a ZIP file containing the signed e-invoice (PDF/A-3 with
  * embedded EN16931 XML), the factur-x.xml and the Mustang validation report.
  */
@@ -33,7 +34,7 @@ public class PdfToolService {
     private final RestClient restClient;
     private final ObjectMapper objectMapper;
 
-    public PdfToolService(@Value("${app.pdftool.base-url:http://localhost:8083}") String baseUrl,
+    public PdfToolService(@Value("${app.pdftool.base-url:http://localhost:8084/api/v1}") String baseUrl,
             ObjectMapper objectMapper) {
         SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
         requestFactory.setConnectTimeout(5000);
@@ -83,7 +84,7 @@ public class PdfToolService {
         body.part("metadata", metadataJson, MediaType.APPLICATION_JSON);
 
         try {
-            ResponseEntity<byte[]> response = restClient.post().uri("/api/invoices/sign")
+            ResponseEntity<byte[]> response = restClient.post().uri("/invoices/sign")
                     .contentType(MediaType.MULTIPART_FORM_DATA).body(body.build()).retrieve()
                     .toEntity(byte[].class);
             return toSignedInvoice(response.getBody(), response.getHeaders(), metadata);
diff --git a/backend/src/main/resources/application.properties b/backend/src/main/resources/application.properties
index c90250a..459fe51 100644
--- a/backend/src/main/resources/application.properties
+++ b/backend/src/main/resources/application.properties
@@ -76,7 +76,7 @@ app.version=@project.version@
 app.google.maps.api-key=AIzaSyDnbitL06iLp3elmj-WtPudCykX9xvXcVE
 
 # PDF Tool (ZUGFeRD-E-Rechnungs-Konverter), Basis-URL des externen Service
-app.pdftool.base-url=${PDFTOOL_BASE_URL:http://localhost:8083}
+app.pdftool.base-url=${PDFTOOL_BASE_URL:http://localhost:8084/api/v1}
 
 # ===========================================
 # LLM Configuration (Anthropic Claude)