diff --git a/apps/main/src/components/ChatMessages.tsx b/apps/main/src/components/ChatMessages.tsx
index 5272e93..173dff7 100644
--- a/apps/main/src/components/ChatMessages.tsx
+++ b/apps/main/src/components/ChatMessages.tsx
@@ -13,6 +13,9 @@ interface ChatMessage {
   createdAt: string;
   clientId: string;
   optimistic?: boolean;
+  // REST API returns snake_case fields from DB, WS messages use camelCase
+  user_id?: string;
+  created_at?: string;
 }
 
 interface Member {
@@ -64,14 +67,16 @@ export function ChatMessages({
   const chatMessages = useMemo<ChatMessageData[]>(
     () =>
       messages.map((msg) => {
-        const member = membersById.get(msg.userId);
+        const userId = msg.userId || msg.user_id || "";
+        const createdAt = msg.createdAt || msg.created_at || "";
+        const member = membersById.get(userId);
         return {
           id: msg.id,
-          senderId: msg.userId,
+          senderId: userId,
           senderName: member?.name ?? "Utilisateur",
           senderAvatar: member?.avatar_url ?? undefined,
           text: msg.text,
-          timestamp: new Date(msg.createdAt),
+          timestamp: new Date(createdAt),
           status: msg.optimistic ? "sending" : undefined,
         };
       }),