diff --git a/src/main/java/eu/hbp/mip/controllers/VariablesApi.java b/src/main/java/eu/hbp/mip/controllers/VariablesApi.java
index d49afd7046ca74395b7a00ee2d767c98a236f982..62f386374de6debba39a9df30a9e160154b51fb4 100644
--- a/src/main/java/eu/hbp/mip/controllers/VariablesApi.java
+++ b/src/main/java/eu/hbp/mip/controllers/VariablesApi.java
@@ -159,6 +159,7 @@ public class VariablesApi {
                 grp.addProperty("code", element.getAsJsonPrimitive("code").getAsString());
                 grp.addProperty("label", element.getAsJsonPrimitive("label").getAsString());
                 var.getAsJsonObject().add("group", grp);
+                var.getAsJsonObject().addProperty("isVariable", true);
                 variables.add(new Gson().toJson(var));
             }
         }