diff --git a/src/main/java/org/ntlab/acanthus_server/entities/InvitesJson.java b/src/main/java/org/ntlab/acanthus_server/entities/InvitesJson.java
index 48a4d53..d3cd98a 100644
--- a/src/main/java/org/ntlab/acanthus_server/entities/InvitesJson.java
+++ b/src/main/java/org/ntlab/acanthus_server/entities/InvitesJson.java
@@ -2,12 +2,13 @@
 
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+import java.util.ArrayList;
 import java.util.Collection;
 
 public class InvitesJson {
 
     @JsonProperty("invites")
-    private Collection<Integer> invites;
+    private Collection<Integer> invites = new ArrayList<>();
 
     public  InvitesJson(Collection<Account> accounts) {
         for(Account inviter : accounts){