diff --git a/src/actors/openid_sessions_actor.rs b/src/actors/openid_sessions_actor.rs
index e611a15..577868c 100644
--- a/src/actors/openid_sessions_actor.rs
+++ b/src/actors/openid_sessions_actor.rs
@@ -46,7 +46,7 @@ impl Session {
                                                 jwt_signer: &JWTSigner) -> Res {
         let access_token = AccessToken {
             issuer: app_config.website_origin.to_string(),
-            subject_identifier: self.user.clone(),
+            subject_identifier: self.user.clone().0,
             issued_at: time(),
             exp_time: time() + OPEN_ID_ACCESS_TOKEN_TIMEOUT,
             rand_val: rand_str(OPEN_ID_ACCESS_TOKEN_LEN),
diff --git a/src/controllers/admin_api.rs b/src/controllers/admin_api.rs
index cacbc52..039ba62 100644
--- a/src/controllers/admin_api.rs
+++ b/src/controllers/admin_api.rs
@@ -18,7 +18,7 @@ struct FindUserResult {
 pub async fn find_username(req: web::Form<FindUserNameReq>, users: web::Data<Addr<UsersActor>>) -> impl Responder {
     let res = users.send(FindUserByUsername(req.0.username)).await.unwrap();
     HttpResponse::Ok().json(FindUserResult {
-        user_id: res.0.map(|r| r.uid)
+        user_id: res.0.map(|r| r.uid.0)
     })
 }
 
diff --git a/src/controllers/openid_controller.rs b/src/controllers/openid_controller.rs
index 1ea6fc2..625884d 100644
--- a/src/controllers/openid_controller.rs
+++ b/src/controllers/openid_controller.rs
@@ -341,7 +341,7 @@ pub async fn token(req: HttpRequest,
             // Generate id token
             let id_token = IdToken {
                 issuer: app_config.website_origin.to_string(),
-                subject_identifier: session.user,
+                subject_identifier: session.user.0,
                 audience: session.client.0.to_string(),
                 expiration_time: session.access_token_expire_at,
                 issued_at: time(),
@@ -499,7 +499,7 @@ async fn user_info(req: HttpRequest, token: Option<String>,
     HttpResponse::Ok()
         .json(OpenIDUserInfo {
             name: user.full_name(),
-            sub: user.uid,
+            sub: user.uid.0,
             given_name: user.first_name,
             family_name: user.last_name,
             preferred_username: user.username,
diff --git a/src/data/session_identity.rs b/src/data/session_identity.rs
index 1286041..28312ca 100644
--- a/src/data/session_identity.rs
+++ b/src/data/session_identity.rs
@@ -20,7 +20,7 @@ impl Default for SessionStatus {
 
 #[derive(Debug, Serialize, Deserialize, Default)]
 pub struct SessionIdentityData {
-    pub id: UserID,
+    pub id: Option<UserID>,
     pub is_admin: bool,
     pub auth_time: u64,
     pub status: SessionStatus,
@@ -48,7 +48,7 @@ impl<'a> SessionIdentity<'a> {
 
         // Check if session is valid
         if let Some(sess) = &res {
-            if sess.id.is_empty() {
+            if sess.id.is_none() {
                 return None;
             }
         }
@@ -64,7 +64,7 @@ impl<'a> SessionIdentity<'a> {
 
     pub fn set_user(&self, user: &User) {
         self.set_session_data(&SessionIdentityData {
-            id: user.uid.clone(),
+            id: Some(user.uid.clone()),
             is_admin: user.admin,
             auth_time: time(),
             status: SessionStatus::SignedIn,
@@ -101,6 +101,7 @@ impl<'a> SessionIdentity<'a> {
 
     pub fn user_id(&self) -> UserID {
         self.get_session_data().unwrap_or_default().id
+            .expect("UserID should never be null here!")
     }
 
     pub fn auth_time(&self) -> u64 {
diff --git a/src/data/user.rs b/src/data/user.rs
index d3196b5..2ee9ecc 100644
--- a/src/data/user.rs
+++ b/src/data/user.rs
@@ -4,7 +4,8 @@ use crate::data::login_redirect::LoginRedirect;
 use crate::data::totp_key::TotpKey;
 use crate::utils::err::Res;
 
-pub type UserID = String;
+#[derive(Clone, Debug, Eq, PartialEq, serde::Serialize, serde::Deserialize)]
+pub struct UserID(pub String);
 
 #[derive(Clone, Debug, Eq, PartialEq, serde::Serialize, serde::Deserialize)]
 pub struct FactorID(pub String);
@@ -101,7 +102,7 @@ impl Eq for User {}
 impl Default for User {
     fn default() -> Self {
         Self {
-            uid: uuid::Uuid::new_v4().to_string(),
+            uid: UserID(uuid::Uuid::new_v4().to_string()),
             first_name: "".to_string(),
             last_name: "".to_string(),
             username: "".to_string(),
diff --git a/templates/settings/account_details.html b/templates/settings/account_details.html
index b60b3ab..f6bb246 100644
--- a/templates/settings/account_details.html
+++ b/templates/settings/account_details.html
@@ -5,7 +5,7 @@
     <tbody>
     <tr>
         <th scope="row">User ID</th>
-        <td>{{ u.uid }}</td>
+        <td>{{ u.uid.0 }}</td>
     </tr>
     <tr>
         <th scope="row">First name</th>
diff --git a/templates/settings/edit_user.html b/templates/settings/edit_user.html
index 9f0ee09..094916b 100644
--- a/templates/settings/edit_user.html
+++ b/templates/settings/edit_user.html
@@ -6,7 +6,7 @@
     <div class="form-group">
         <label class="form-label mt-4" for="userID">User ID</label>
         <input class="form-control" id="userID" type="text" readonly=""
-               name="uid" value="{{ u.uid }}"/>
+               name="uid" value="{{ u.uid.0 }}"/>
     </div>
 
     <!-- User name -->
@@ -145,7 +145,7 @@
                     return;
 
                 const userID = await find_username(usernameEl.value);
-                usernameEl.classList.add((userID === null || userID === "{{ u.uid }}") ? "is-valid" : "is-invalid");
+                usernameEl.classList.add((userID === null || userID === "{{ u.uid.0 }}") ? "is-valid" : "is-invalid");
 
             } catch(e) {
                 console.error(e);
diff --git a/templates/settings/users_list.html b/templates/settings/users_list.html
index f91aa45..aae775f 100644
--- a/templates/settings/users_list.html
+++ b/templates/settings/users_list.html
@@ -19,7 +19,7 @@
     </thead>
     <tbody>
     {% for u in users %}
-    <tr id="row-user-{{ u.uid }}">
+    <tr id="row-user-{{ u.uid.0 }}">
         <td>{{ u.username }}</td>
         <td>{{ u.first_name }}</td>
         <td>{{ u.last_name }}</td>
@@ -27,8 +27,8 @@
         <td>{% if u.admin %}Admin{% else %}Regular user{% endif %}</td>
         <td>{% if u.enabled %}Enabled{% else %}Disabled{% endif %}</td>
         <td>
-            <a href="/admin/edit_user?id={{ u.uid }}">Edit</a>
-            <a href="javascript:delete_user('{{ u.uid }}', '{{ u.username }}')">Delete</a>
+            <a href="/admin/edit_user?id={{ u.uid.0 }}">Edit</a>
+            <a href="javascript:delete_user('{{ u.uid.0 }}', '{{ u.username }}')">Delete</a>
         </td>
     </tr>
     {% endfor %}