diff --git a/executor/api/util/utils.go b/executor/api/util/utils.go
index 9309d65e02..3a72a06f5e 100644
--- a/executor/api/util/utils.go
+++ b/executor/api/util/utils.go
@@ -10,7 +10,11 @@ func ExtractRouteFromSeldonMessage(msg *proto.SeldonMessage) []int {
 		values := msg.GetData().GetNdarray().GetValues()
 		routeArr := make([]int, len(values))
 		for i, value := range values {
-			routeArr[i] = int(value.GetNumberValue())
+			if listValue := value.GetListValue(); listValue != nil {
+				routeArr[i] = int(listValue.GetValues()[0].GetNumberValue())
+			} else {
+				routeArr[i] = int(value.GetNumberValue())
+			}
 		}
 		return routeArr
 	case *proto.DefaultData_Tensor:
diff --git a/executor/api/util/utils_test.go b/executor/api/util/utils_test.go
new file mode 100644
index 0000000000..b70d92d6ae
--- /dev/null
+++ b/executor/api/util/utils_test.go
@@ -0,0 +1,47 @@
+package util
+
+import (
+	"testing"
+
+	"github.com/golang/protobuf/jsonpb"
+	. "github.com/onsi/gomega"
+	"github.com/seldonio/seldon-core/executor/api/grpc/seldon/proto"
+)
+
+func TestExtractRouteFromSeldonMessage(t *testing.T) {
+	g := NewGomegaWithT(t)
+
+	cases := []struct {
+		msg      string
+		expected []int
+	}{
+		{
+			msg:      `{"data":{"names":["X1L"],"ndarray":[[1]]}}`,
+			expected: []int{1},
+		},
+		{
+			msg:      `{"data":{"ndarray":[2]}}`,
+			expected: []int{2},
+		},
+		{
+			msg:      `{"data":{"ndarray":[3,4]}}`,
+			expected: []int{3, 4},
+		},
+		{
+			msg:      `{"data":{"names":["X1L","X2L"],"ndarray":[[1,2],[3,4]]}}`,
+			expected: []int{1, 3},
+		},
+		{
+			msg:      `{"data":{"ndarray":[]}}`,
+			expected: []int{},
+		},
+	}
+
+	for _, c := range cases {
+		var sm proto.SeldonMessage
+		jsonpb.UnmarshalString(c.msg, &sm)
+		routes := ExtractRouteFromSeldonMessage(&sm)
+
+		g.Expect(routes).To(Equal(c.expected))
+	}
+}