diff --git a/src/main/java/de/bund/digitalservice/a2j/controller/SenderController.java b/src/main/java/de/bund/digitalservice/a2j/controller/SenderController.java
index 2123d81..47b3f78 100644
--- a/src/main/java/de/bund/digitalservice/a2j/controller/SenderController.java
+++ b/src/main/java/de/bund/digitalservice/a2j/controller/SenderController.java
@@ -1,6 +1,7 @@
 package de.bund.digitalservice.a2j.controller;
 
 import de.bund.digitalservice.a2j.service.SenderService;
+import de.bund.digitalservice.a2j.service.SubmitRequest;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
@@ -17,9 +18,9 @@ public SenderController(SenderService service) {
   }
 
   @PostMapping("/submit")
-  public ResponseEntity<String> submitMessage(@RequestBody String message) {
+  public ResponseEntity<String> submit(@RequestBody SubmitRequest submitRequest) {
     try {
-      String response = service.sendMessage(message);
+      String response = service.submit(submitRequest);
       return ResponseEntity.ok("Submission successful, content: " + response);
     } catch (Exception e) {
       return ResponseEntity.internalServerError().body("Error: " + e.getMessage());
diff --git a/src/main/java/de/bund/digitalservice/a2j/service/FitConnectSenderService.java b/src/main/java/de/bund/digitalservice/a2j/service/FitConnectSenderService.java
index 70dc2ac..6a4be4b 100644
--- a/src/main/java/de/bund/digitalservice/a2j/service/FitConnectSenderService.java
+++ b/src/main/java/de/bund/digitalservice/a2j/service/FitConnectSenderService.java
@@ -22,13 +22,12 @@ public FitConnectSenderService(ApplicationConfig config) {
   }
 
   @Override
-  public String sendMessage(String message) {
-
+  public String submit(SubmitRequest submitRequest) {
     SendableSubmission submission =
         SendableSubmission.Builder()
             .setDestination(UUID.fromString("89126fd7-1069-46f1-9cdc-152037db95a9"))
             .setServiceType("urn:de:fim:leika:leistung:99400048079000", "Simple Dummy Service")
-            .setJsonData(buildJSON(message), URI.create("urn:de:fim:leika:leistung:99400048079000"))
+            .setJsonData(buildJSON(submitRequest.message()), URI.create("urn:data"))
             .build();
 
     try {
diff --git a/src/main/java/de/bund/digitalservice/a2j/service/SenderService.java b/src/main/java/de/bund/digitalservice/a2j/service/SenderService.java
index f7fdc81..b3f9ef6 100644
--- a/src/main/java/de/bund/digitalservice/a2j/service/SenderService.java
+++ b/src/main/java/de/bund/digitalservice/a2j/service/SenderService.java
@@ -1,5 +1,5 @@
 package de.bund.digitalservice.a2j.service;
 
 public interface SenderService {
-  String sendMessage(String message);
+  String submit(SubmitRequest submitRequest);
 }
diff --git a/src/main/java/de/bund/digitalservice/a2j/service/SubmitRequest.java b/src/main/java/de/bund/digitalservice/a2j/service/SubmitRequest.java
new file mode 100644
index 0000000..29b3e9c
--- /dev/null
+++ b/src/main/java/de/bund/digitalservice/a2j/service/SubmitRequest.java
@@ -0,0 +1,3 @@
+package de.bund.digitalservice.a2j.service;
+
+public record SubmitRequest(String message) {}