diff --git a/lib/types/link-types.js b/lib/types/link-types.js
--- a/lib/types/link-types.js
+++ b/lib/types/link-types.js
@@ -35,8 +35,8 @@
   primary: t.Boolean,
   role: tID,
   communityID: tID,
-  expirationTime: t.Number,
-  limitOfUses: t.Number,
+  expirationTime: t.maybe(t.Number),
+  limitOfUses: t.maybe(t.Number),
   numberOfUses: t.Number,
 });