diff --git a/backend/src/main/java/org/raddatz/familienarchiv/controller/OcrController.java b/backend/src/main/java/org/raddatz/familienarchiv/controller/OcrController.java
index cb48caca..4ada18e4 100644
--- a/backend/src/main/java/org/raddatz/familienarchiv/controller/OcrController.java
+++ b/backend/src/main/java/org/raddatz/familienarchiv/controller/OcrController.java
@@ -27,7 +27,6 @@ import org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBo
 import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
 
 import jakarta.validation.Valid;
-import java.util.HashMap;
 import java.util.Map;
 import java.util.UUID;
 
@@ -131,19 +130,8 @@ public class OcrController {
 
     @GetMapping("/api/ocr/training-info")
     @RequirePermission(Permission.ADMIN)
-    public Map<String, Object> getTrainingInfo() {
-        OcrTrainingService.TrainingInfoResponse info = ocrTrainingService.getTrainingInfo();
-
-        Map<String, Object> result = new HashMap<>();
-        result.put("availableBlocks", info.availableBlocks());
-        result.put("totalOcrBlocks", info.totalOcrBlocks());
-        result.put("availableDocuments", info.availableDocuments());
-        result.put("availableSegBlocks", info.availableSegBlocks());
-        result.put("ocrServiceAvailable", info.ocrServiceAvailable());
-        result.put("lastRun", info.lastRun() != null ? info.lastRun() : Map.of());
-        result.put("runs", info.runs());
-        result.put("personNames", info.personNames());
-        return result;
+    public OcrTrainingService.TrainingInfoResponse getTrainingInfo() {
+        return ocrTrainingService.getTrainingInfo();
     }
 
     private UUID resolveUserId(Authentication authentication) {
diff --git a/backend/src/test/java/org/raddatz/familienarchiv/controller/OcrControllerTest.java b/backend/src/test/java/org/raddatz/familienarchiv/controller/OcrControllerTest.java
index 5313b267..e65e490c 100644
--- a/backend/src/test/java/org/raddatz/familienarchiv/controller/OcrControllerTest.java
+++ b/backend/src/test/java/org/raddatz/familienarchiv/controller/OcrControllerTest.java
@@ -264,6 +264,18 @@ class OcrControllerTest {
                 .andExpect(jsonPath("$.personNames." + personId).value("Max Mustermann"));
     }
 
+    @Test
+    @WithMockUser(authorities = "ADMIN")
+    void getTrainingInfo_serializes_null_lastRun_as_json_null() throws Exception {
+        OcrTrainingService.TrainingInfoResponse info =
+                new OcrTrainingService.TrainingInfoResponse(0, 0, 0, 0, false, null, List.of(), Map.of());
+        when(ocrTrainingService.getTrainingInfo()).thenReturn(info);
+
+        mockMvc.perform(get("/api/ocr/training-info"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$.lastRun").doesNotExist());
+    }
+
     @Test
     @WithMockUser(authorities = "READ_ALL")
     void getDocumentOcrStatus_returnsNone_whenNoOcrJobExists() throws Exception {