diff --git a/samples/server/petstore/graphql-nodejs-express-server/petstore/model/pet.graphql b/samples/server/petstore/graphql-nodejs-express-server/petstore/model/pet.graphql
index 54cafbe0233..17923b7b179 100644
--- a/samples/server/petstore/graphql-nodejs-express-server/petstore/model/pet.graphql
+++ b/samples/server/petstore/graphql-nodejs-express-server/petstore/model/pet.graphql
@@ -13,8 +13,8 @@ type Pet {
   id: Int!
   category: Category
   name: String!
-  photoUrls: String!
-  tags: Tag
+  photoUrls: [String!!]
+  tags: [Tag!]
   # pet status in the store
   status: StatusEnum
 }