diff --git a/src/contact/mod.rs b/src/contact/mod.rs
index 973a2d7..9eba279 100644
--- a/src/contact/mod.rs
+++ b/src/contact/mod.rs
@@ -2,14 +2,19 @@ use serde::{Deserialize, Serialize};
 
 #[derive(Clone, Debug, Default, Deserialize, Serialize)]
 pub struct Contact {
-    pub id: uuid::Uuid,
+    #[serde(skip_serializing_if = "crate::init::is_uuid_nil")]
+    pub id: Option<uuid::Uuid>,
     // empty?
-    pub firstname: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub firstname: Option<String>,
     // empty?
-    pub lastname: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub lastname: Option<String>,
     // empty?
-    pub nickname: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub nickname: Option<String>,
     pub phone_number: String,
     // empty
-    pub user_id: uuid::Uuid,
+    #[serde(skip_serializing_if = "crate::init::is_uuid_nil")]
+    pub user_id: Option<uuid::Uuid>,
 }
diff --git a/src/lib.rs b/src/lib.rs
index bed7751..6dd050f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,7 +6,10 @@ pub mod token;
 pub mod user;
 
 pub mod init {
-    pub fn is_uuid_nil(uuid: &uuid::Uuid) -> bool {
-        uuid.is_nil()
+    pub fn is_uuid_nil(uuid: &Option<uuid::Uuid>) -> bool {
+        match uuid {
+            Some(id) => id.is_nil(),
+            None => true,
+        }
     }
 }
diff --git a/src/user/mod.rs b/src/user/mod.rs
index 2a891fc..e2d4f66 100644
--- a/src/user/mod.rs
+++ b/src/user/mod.rs
@@ -71,7 +71,7 @@ pub struct UserProfile {
 
 #[derive(Clone, Debug, Default, Deserialize, Serialize)]
 pub struct Salt {
-    #[serde(skip_serializing_if = "crate::init::is_uuid_nil")]
+    // #[serde(skip_serializing_if = "crate::init::is_uuid_nil")]
     pub id: uuid::Uuid,
     #[serde(skip_serializing_if = "String::is_empty")]
     pub salt: String,