diff --git a/apps/api/libs/handlers/src/chats/get_chat_handler.rs b/apps/api/libs/handlers/src/chats/get_chat_handler.rs
index ee61bbfe5..04b9310eb 100644
--- a/apps/api/libs/handlers/src/chats/get_chat_handler.rs
+++ b/apps/api/libs/handlers/src/chats/get_chat_handler.rs
@@ -43,6 +43,7 @@ pub struct MessageWithUser {
     pub updated_at: DateTime<Utc>,
     pub user_id: Uuid,
     pub user_name: Option<String>,
+    pub user_email: String,
     pub user_avatar_url: Option<String>,
     pub feedback: Option<String>,
     pub is_completed: bool,
@@ -137,6 +138,7 @@ pub async fn get_chat_handler(
                     messages::updated_at,
                     users::id,
                     users::name.nullable(),
+                    users::email,
                     users::avatar_url.nullable(),
                     messages::feedback.nullable(),
                     messages::is_completed,
@@ -274,7 +276,7 @@ pub async fn get_chat_handler(
                 Some(ChatUserMessage {
                     request: Some(request_message),
                     sender_id: msg.user_id,
-                    sender_name: msg.user_name.unwrap_or_else(|| "Unknown".to_string()),
+                    sender_name: msg.user_name.unwrap_or_else(|| msg.user_email.clone()),
                     sender_avatar: msg.user_avatar_url,
                 })
             } else {
@@ -353,7 +355,7 @@ pub async fn get_chat_handler(
         thread_messages,
         false, // is_favorited not implemented in current schema
         thread.user_id.to_string(),
-        thread.user_name.unwrap_or_else(|| "Unknown".to_string()),
+        thread.user_name.unwrap_or_else(|| thread.user_email.clone()),
         created_by_avatar,
     );
 
diff --git a/apps/api/libs/handlers/src/chats/list_chats_handler.rs b/apps/api/libs/handlers/src/chats/list_chats_handler.rs
index 554f58926..520b22dcd 100644
--- a/apps/api/libs/handlers/src/chats/list_chats_handler.rs
+++ b/apps/api/libs/handlers/src/chats/list_chats_handler.rs
@@ -63,6 +63,7 @@ struct ChatWithUser {
     pub most_recent_version_number: Option<i32>,
     // User fields
     pub user_name: Option<String>,
+    pub user_email: String,
     pub user_avatar_url: Option<String>,
 }
 
@@ -144,6 +145,7 @@ pub async fn list_chats_handler(
             chats::most_recent_file_type,
             chats::most_recent_version_number,
             users::name.nullable(),
+            users::email,
             users::avatar_url.nullable(),
         ))
         .load::<ChatWithUser>(&mut conn)
@@ -235,6 +237,7 @@ pub async fn list_chats_handler(
                 chats::most_recent_file_type,
                 chats::most_recent_version_number,
                 users::name.nullable(),
+                users::email,
                 users::avatar_url.nullable(),
             ))
             .order_by(chats::updated_at.desc())
@@ -258,7 +261,7 @@ pub async fn list_chats_handler(
                 updated_at: chat.updated_at.to_rfc3339(),
                 created_by: chat.created_by.to_string(),
                 created_by_id: chat.created_by.to_string(),
-                created_by_name: chat.user_name.unwrap_or_else(|| "Unknown".to_string()),
+                created_by_name: chat.user_name.unwrap_or_else(|| chat.user_email.clone()),
                 created_by_avatar: chat.user_avatar_url,
                 last_edited: chat.updated_at.to_rfc3339(),
                 latest_file_id: chat.most_recent_file_id.map(|id| id.to_string()),
@@ -280,7 +283,7 @@ pub async fn list_chats_handler(
                 updated_at: chat.updated_at.to_rfc3339(),
                 created_by: chat.created_by.to_string(),
                 created_by_id: chat.created_by.to_string(),
-                created_by_name: chat.user_name.unwrap_or_else(|| "Unknown".to_string()),
+                created_by_name: chat.user_name.unwrap_or_else(|| chat.user_email.clone()),
                 created_by_avatar: chat.user_avatar_url,
                 last_edited: chat.updated_at.to_rfc3339(),
                 latest_file_id: chat.most_recent_file_id.map(|id| id.to_string()),
diff --git a/apps/api/libs/handlers/src/logs/list_logs_handler.rs b/apps/api/libs/handlers/src/logs/list_logs_handler.rs
index 09d65fabe..cc4d0f7a0 100644
--- a/apps/api/libs/handlers/src/logs/list_logs_handler.rs
+++ b/apps/api/libs/handlers/src/logs/list_logs_handler.rs
@@ -55,6 +55,7 @@ struct ChatWithUser {
     pub most_recent_version_number: Option<i32>,
     // User fields
     pub user_name: Option<String>,
+    pub user_email: String,
     pub user_avatar_url: Option<String>,
 }
 
@@ -116,6 +117,7 @@ pub async fn list_logs_handler(
             chats::most_recent_file_type,
             chats::most_recent_version_number,
             users::name.nullable(),
+            users::email,
             users::avatar_url.nullable(),
         ))
         .load::<ChatWithUser>(&mut conn)
@@ -135,7 +137,7 @@ pub async fn list_logs_handler(
                 updated_at: chat.updated_at.to_rfc3339(),
                 created_by: chat.created_by.to_string(),
                 created_by_id: chat.created_by.to_string(),
-                created_by_name: chat.user_name.unwrap_or_else(|| "Unknown".to_string()),
+                created_by_name: chat.user_name.unwrap_or_else(|| chat.user_email.clone()),
                 created_by_avatar: chat.user_avatar_url,
                 last_edited: chat.updated_at.to_rfc3339(),
                 latest_file_id: chat.most_recent_file_id.map(|id| id.to_string()),
diff --git a/apps/server/src/api/v2/chats/services/chat-helpers.ts b/apps/server/src/api/v2/chats/services/chat-helpers.ts
index 0932b3821..0c76d2310 100644
--- a/apps/server/src/api/v2/chats/services/chat-helpers.ts
+++ b/apps/server/src/api/v2/chats/services/chat-helpers.ts
@@ -114,7 +114,7 @@ export function buildChatWithMessages(
   const messageIds: string[] = new Array(messageCount);
 
   // Cache user info to avoid repeated property access
-  const userName = user?.name || 'Unknown User';
+  const userName = user?.name || user?.email || 'Unknown User';
   const userAvatar = user?.avatarUrl || undefined;
 
   // Single iteration with optimized object creation