diff --git a/app/views/repositories/_contributor.json.jbuilder b/app/views/repositories/_contributor.json.jbuilder
index 2efaa0073..ed8a581a6 100644
--- a/app/views/repositories/_contributor.json.jbuilder
+++ b/app/views/repositories/_contributor.json.jbuilder
@@ -13,5 +13,8 @@ else
   json.type user["type"]
   json.name user["name"]
   json.image_url user["avatar_url"]
-  json.blockchain_perc user.contribution_perc(project)
+  if project.use_blockchain 
+    db_user = User.find_by_id(user["id"])
+    json.blockchain_perc db_user.contribution_perc(project)
+  end
 end