diff --git a/backend/internal/handlers/objects.go b/backend/internal/handlers/objects.go
index ab43050..3edcee3 100644
--- a/backend/internal/handlers/objects.go
+++ b/backend/internal/handlers/objects.go
@@ -9,6 +9,7 @@ import (
 	"strings"
 	"time"
 
+	"Noooste/garage-ui/internal/apierr"
 	"Noooste/garage-ui/internal/models"
 	"Noooste/garage-ui/internal/services"
 
@@ -122,9 +123,7 @@ func (h *ObjectHandler) ListObjects(c fiber.Ctx) error {
 	// List objects in the bucket
 	objects, err := h.s3Service.ListObjects(ctx, bucketName, prefix, maxKeys, continuationToken)
 	if err != nil {
-		return c.Status(fiber.StatusInternalServerError).JSON(
-			models.ErrorResponse(models.ErrCodeListFailed, "Failed to list objects: "+err.Error()),
-		)
+		return apierr.Respond(c, err)
 	}
 
 	return c.JSON(models.SuccessResponse(objects))
@@ -186,9 +185,7 @@ func (h *ObjectHandler) UploadObject(c fiber.Ctx) error {
 	// Upload to Garage
 	uploadResult, err := h.s3Service.UploadObject(ctx, bucketName, key, fileHandle, contentType)
 	if err != nil {
-		return c.Status(fiber.StatusInternalServerError).JSON(
-			models.ErrorResponse(models.ErrCodeUploadFailed, "Failed to upload object: "+err.Error()),
-		)
+		return apierr.Respond(c, err)
 	}
 
 	return c.Status(fiber.StatusCreated).JSON(models.SuccessResponse(uploadResult))
@@ -238,9 +235,7 @@ func (h *ObjectHandler) CreateDirectory(c fiber.Ctx) error {
 
 	result, err := h.s3Service.CreateDirectoryMarker(ctx, bucketName, key)
 	if err != nil {
-		return c.Status(fiber.StatusInternalServerError).JSON(
-			models.ErrorResponse(models.ErrCodeUploadFailed, "Failed to create directory: "+err.Error()),
-		)
+		return apierr.Respond(c, err)
 	}
 
 	return c.Status(fiber.StatusCreated).JSON(models.SuccessResponse(result))
@@ -281,9 +276,7 @@ func (h *ObjectHandler) GetObject(c fiber.Ctx) error {
 	// Get object from Garage
 	body, objectInfo, err := h.s3Service.GetObject(ctx, bucketName, key)
 	if err != nil {
-		return c.Status(fiber.StatusNotFound).JSON(
-			models.ErrorResponse(models.ErrCodeObjectNotFound, "Object not found: "+err.Error()),
-		)
+		return apierr.Respond(c, err)
 	}
 
 	// The uploader controls Content-Type. Rewrite executable MIME types to
@@ -345,9 +338,7 @@ func (h *ObjectHandler) DeleteObject(c fiber.Ctx) error {
 	// Check if object exists
 	exists, err := h.s3Service.ObjectExists(ctx, bucketName, key)
 	if err != nil {
-		return c.Status(fiber.StatusInternalServerError).JSON(
-			models.ErrorResponse(models.ErrCodeInternalError, "Failed to check object existence: "+err.Error()),
-		)
+		return apierr.Respond(c, err)
 	}
 
 	if !exists {
@@ -358,9 +349,7 @@ func (h *ObjectHandler) DeleteObject(c fiber.Ctx) error {
 
 	// Delete the object
 	if err := h.s3Service.DeleteObject(ctx, bucketName, key); err != nil {
-		return c.Status(fiber.StatusInternalServerError).JSON(
-			models.ErrorResponse(models.ErrCodeDeleteFailed, "Failed to delete object: "+err.Error()),
-		)
+		return apierr.Respond(c, err)
 	}
 
 	// Return success response
@@ -407,9 +396,7 @@ func (h *ObjectHandler) GetObjectMetadata(c fiber.Ctx) error {
 	// Get object metadata
 	metadata, err := h.s3Service.GetObjectMetadata(ctx, bucketName, key)
 	if err != nil {
-		return c.Status(fiber.StatusNotFound).JSON(
-			models.ErrorResponse(models.ErrCodeObjectNotFound, "Object not found: "+err.Error()),
-		)
+		return apierr.Respond(c, err)
 	}
 
 	return c.JSON(models.SuccessResponse(metadata))
@@ -467,9 +454,7 @@ func (h *ObjectHandler) GetPresignedURL(c fiber.Ctx) error {
 	// Check if object exists
 	exists, err := h.s3Service.ObjectExists(ctx, bucketName, key)
 	if err != nil {
-		return c.Status(fiber.StatusInternalServerError).JSON(
-			models.ErrorResponse(models.ErrCodeInternalError, "Failed to check object existence: "+err.Error()),
-		)
+		return apierr.Respond(c, err)
 	}
 
 	if !exists {
@@ -481,9 +466,7 @@ func (h *ObjectHandler) GetPresignedURL(c fiber.Ctx) error {
 	// Generate pre-signed URL
 	url, err := h.s3Service.GetPresignedURL(ctx, bucketName, key, time.Duration(expiresIn)*time.Second)
 	if err != nil {
-		return c.Status(fiber.StatusInternalServerError).JSON(
-			models.ErrorResponse(models.ErrCodeInternalError, "Failed to generate pre-signed URL: "+err.Error()),
-		)
+		return apierr.Respond(c, err)
 	}
 
 	response := models.PresignedURLResponse{
@@ -540,9 +523,7 @@ func (h *ObjectHandler) DeleteMultipleObjects(c fiber.Ctx) error {
 
 	// Delete multiple objects
 	if err := h.s3Service.DeleteMultipleObjects(ctx, bucketName, req.Keys); err != nil {
-		return c.Status(fiber.StatusInternalServerError).JSON(
-			models.ErrorResponse(models.ErrCodeDeleteFailed, "Failed to delete objects: "+err.Error()),
-		)
+		return apierr.Respond(c, err)
 	}
 
 	response := models.ObjectDeleteMultipleResponse{
diff --git a/backend/internal/handlers/objects_test.go b/backend/internal/handlers/objects_test.go
index 8cbb3f1..ee066c5 100644
--- a/backend/internal/handlers/objects_test.go
+++ b/backend/internal/handlers/objects_test.go
@@ -144,18 +144,20 @@ func TestGetObjectMetadata_Success(t *testing.T) {
 	}
 }
 
-func TestGetObjectMetadata_NotFound404(t *testing.T) {
+func TestGetObjectMetadata_ServiceError500(t *testing.T) {
 	app, s3 := newObjectsTestApp(t)
 	s3.GetObjectMetadataFn = func(_ context.Context, _, _ string) (*models.ObjectInfo, error) {
-		return nil, errors.New("not found")
+		return nil, errors.New("boom")
 	}
 	resp, err := app.Test(httptest.NewRequest(http.MethodGet, "/buckets/b1/objects/nope/metadata", nil))
 	if err != nil {
 		t.Fatalf("app.Test: %v", err)
 	}
 	defer resp.Body.Close()
-	if resp.StatusCode != http.StatusNotFound {
-		t.Fatalf("status = %d, want 404", resp.StatusCode)
+	// Generic errors map to 500/INTERNAL_ERROR; typed upstream NoSuchKey → 404
+	// is covered by Task 12 tests.
+	if resp.StatusCode != http.StatusInternalServerError {
+		t.Fatalf("status = %d, want 500", resp.StatusCode)
 	}
 }
 
@@ -363,18 +365,20 @@ func TestGetObject_DownloadQuerySetsAttachment(t *testing.T) {
 	}
 }
 
-func TestGetObject_ServiceErrorReturns404(t *testing.T) {
+func TestGetObject_ServiceErrorReturns500(t *testing.T) {
 	app, s3 := newObjectsTestApp(t)
 	s3.GetObjectFn = func(_ context.Context, _, _ string) (io.ReadCloser, *models.ObjectInfo, error) {
-		return nil, nil, errors.New("not found")
+		return nil, nil, errors.New("boom")
 	}
 	resp, err := app.Test(httptest.NewRequest(http.MethodGet, "/buckets/b1/objects/nope", nil))
 	if err != nil {
 		t.Fatalf("app.Test: %v", err)
 	}
 	defer resp.Body.Close()
-	if resp.StatusCode != http.StatusNotFound {
-		t.Fatalf("status = %d, want 404", resp.StatusCode)
+	// Generic errors map to 500/INTERNAL_ERROR; typed upstream NoSuchKey → 404
+	// is covered by Task 12 tests.
+	if resp.StatusCode != http.StatusInternalServerError {
+		t.Fatalf("status = %d, want 500", resp.StatusCode)
 	}
 }