diff --git a/web/src/components/ConversationList.tsx b/web/src/components/ConversationList.tsx
index 181e074..993fe39 100644
--- a/web/src/components/ConversationList.tsx
+++ b/web/src/components/ConversationList.tsx
@@ -16,9 +16,10 @@ function isSelfDM(conv: { members: { id: string }[] }, currentUserId: string) {
 
 export function ConversationList() {
   const conversations = useConversationStore((s) => s.conversations);
-  const activeId = useConversationStore((s) => s.activeConversationId);
+  const activeId = useConversationStore((s) => s.activeConversationId?.toLowerCase() ?? null);
   const fetchConversations = useConversationStore((s) => s.fetchConversations);
   const createConversation = useConversationStore((s) => s.createConversation);
+  const setActiveConversation = useConversationStore((s) => s.setActiveConversation);
   const messagesByConv = useConversationStore((s) => s.messagesByConversation);
   const currentUser = useAuthStore((s) => s.user);
   const hasConvUnread = useReadStatesStore((s) => s.hasConvUnread);
@@ -31,8 +32,9 @@ export function ConversationList() {
     fetchConversations();
   }, [fetchConversations]);
 
-  const openConversation = (convId: string) => {
-    // mark as read when opening
+  const openConversation = (rawId: string) => {
+    const convId = rawId.toLowerCase();
+    setActiveConversation(convId);
     const msgs = messagesByConv[convId] || [];
     if (msgs.length > 0) {
       markConvRead(convId, msgs[msgs.length - 1].id);
@@ -50,7 +52,7 @@ export function ConversationList() {
     try {
       const conv = await createConversation([]);
       if (conv) {
-        navigate(`/dm/${conv.id}`);
+        openConversation(conv.id);
       }
     } catch (err) {
       console.error("Failed to create notes:", err);
@@ -59,7 +61,7 @@ export function ConversationList() {
   };
 
   const getLatestMessageId = (convId: string): string | undefined => {
-    const msgs = messagesByConv[convId] || [];
+    const msgs = messagesByConv[convId.toLowerCase()] || [];
     return msgs.length > 0 ? msgs[msgs.length - 1].id : undefined;
   };
 
@@ -89,19 +91,20 @@ export function ConversationList() {
           <p className="text-gb-fg-f">[no conversations]</p>
         )}
         {conversations.map((conv) => {
+          const convId = conv.id.toLowerCase();
           const self = isSelfDM(conv, currentUser?.id || "");
           const name = self
             ? "Notes"
             : conv.type === "group_dm"
               ? conv.name || conv.members.map((m) => m.username).join(", ")
               : otherMemberName(conv, currentUser?.id || "");
-          const unread = hasConvUnread(conv.id, getLatestMessageId(conv.id));
+          const unread = hasConvUnread(convId, getLatestMessageId(convId));
           return (
             <button
               key={conv.id}
               onClick={() => openConversation(conv.id)}
               className={`w-full text-left px-2 py-1 rounded-sm flex items-center gap-2 ${
-                conv.id === activeId
+                convId === activeId
                   ? "terminal-active"
                   : "hover:bg-gb-bg-t text-gb-fg-s"
               }`}
diff --git a/web/src/components/DMChat.tsx b/web/src/components/DMChat.tsx
index 61bf94c..59952ad 100644
--- a/web/src/components/DMChat.tsx
+++ b/web/src/components/DMChat.tsx
@@ -152,7 +152,6 @@ export function DMChat() {
   const activeId = useConversationStore((s) => s.activeConversationId);
   const setActive = useConversationStore((s) => s.setActiveConversation);
   const conversations = useConversationStore((s) => s.conversations);
-  const messagesByConv = useConversationStore((s) => s.messagesByConversation);
   const fetchMessages = useConversationStore((s) => s.fetchMessages);
   const fetchOlderMessages = useConversationStore((s) => s.fetchOlderMessages);
   const isLoadingOlder = useConversationStore((s) => s.isLoadingOlder);
@@ -173,9 +172,13 @@ export function DMChat() {
   const markConvRead = useReadStatesStore((s) => s.markConvRead);
   const convStates = useReadStatesStore((s) => s.convStates);
 
-  const id = conversationId || activeId;
-  const conversation = conversations.find((c) => c.id === id);
+  const rawId = conversationId || activeId;
+  const id = rawId ? rawId.toLowerCase() : undefined;
+  const conversation = conversations.find((c) => c.id.toLowerCase() === id);
   const hasMore = useConversationStore((s) => id ? s.hasMoreByConversation[id] !== false : true);
+  const messages = useConversationStore(
+    useCallback((s) => (id ? s.messagesByConversation[id] || [] : []), [id])
+  );
 
   const handleAddReaction = useCallback(async (messageId: string, emoji: string) => {
     if (!id) return;
@@ -200,7 +203,6 @@ export function DMChat() {
       });
     }
   }, [id, isLoadingOlder, hasMore, fetchOlderMessages]);
-  const messages = id ? messagesByConv[id] || [] : [];
 
   useEffect(() => {
     fetchConversations();
diff --git a/web/src/stores/conversation.ts b/web/src/stores/conversation.ts
index 1192ce6..ef84dfc 100644
--- a/web/src/stores/conversation.ts
+++ b/web/src/stores/conversation.ts
@@ -79,39 +79,42 @@ export const useConversationStore = create<ConversationState>((set, get) => ({
 
   createConversation: async (userIds) => {
     const conversation = await api.post<Conversation>("/conversations", { user_ids: userIds });
+    const convId = conversation.id.toLowerCase();
+    const normalizedConv = { ...conversation, id: convId };
     set((state) => ({
-      conversations: [conversation, ...state.conversations],
-      activeConversationId: conversation.id,
+      conversations: [normalizedConv, ...state.conversations],
+      activeConversationId: convId,
     }));
-    return conversation;
+    return normalizedConv;
   },
 
-  setActiveConversation: (id) => set({ activeConversationId: id }),
+  setActiveConversation: (id) => set({ activeConversationId: id ? id.toLowerCase() : null }),
 
   fetchMessages: async (conversationId, before) => {
+    const convId = conversationId.toLowerCase();
     set({ isLoading: true });
     try {
       const params = before ? "?before=" + encodeURIComponent(before) : "";
       const messages = await api.get<ConversationMessage[]>(
-        `/conversations/${conversationId}/messages${params}`,
+        `/conversations/${convId}/messages${params}`,
       );
       const list = Array.isArray(messages) ? messages : [];
       set((state) => {
-        const existing = state.messagesByConversation[conversationId] || [];
+        const existing = state.messagesByConversation[convId] || [];
         const map = new Map<string, ConversationMessage>();
         existing.forEach((m) => map.set(m.id, m));
-        list.forEach((m) => map.set(m.id, m));
+        list.forEach((m) => map.set(m.id, { ...m, conversation_id: (m.conversation_id || convId).toLowerCase() }));
         const merged = Array.from(map.values()).sort(
           (a, b) => parseDate(a.created_at) - parseDate(b.created_at)
         );
         return {
           messagesByConversation: {
             ...state.messagesByConversation,
-            [conversationId]: merged,
+            [convId]: merged,
           },
           hasMoreByConversation: {
             ...state.hasMoreByConversation,
-            [conversationId]: list.length >= 50,
+            [convId]: list.length >= 50,
           },
           isLoading: false,
         };
@@ -122,32 +125,32 @@ export const useConversationStore = create<ConversationState>((set, get) => ({
   },
 
   fetchOlderMessages: async (conversationId) => {
+    const convId = conversationId.toLowerCase();
     const state = get();
-    if (state.isLoadingOlder || state.hasMoreByConversation[conversationId] === false) return;
-    const existing = state.messagesByConversation[conversationId] || [];
+    if (state.isLoadingOlder || state.hasMoreByConversation[convId] === false) return;
+    const existing = state.messagesByConversation[convId] || [];
     if (existing.length === 0) return;
-    // ponytail: existing is now oldest-first, so existing[0] is the true oldest
     const oldestId = existing[0].id;
     set({ isLoadingOlder: true });
     try {
       const older = await api.get<ConversationMessage[]>(
-        `/conversations/${conversationId}/messages?before=${encodeURIComponent(oldestId)}`,
+        `/conversations/${convId}/messages?before=${encodeURIComponent(oldestId)}`,
       );
       const list = Array.isArray(older) ? older : [];
       set((state) => {
         const map = new Map<string, ConversationMessage>();
-        [...list, ...existing].forEach((m) => map.set(m.id, m));
+        [...list, ...existing].forEach((m) => map.set(m.id, { ...m, conversation_id: (m.conversation_id || convId).toLowerCase() }));
         const merged = Array.from(map.values()).sort(
           (a, b) => parseDate(a.created_at) - parseDate(b.created_at)
         );
         return {
           messagesByConversation: {
             ...state.messagesByConversation,
-            [conversationId]: merged,
+            [convId]: merged,
           },
           hasMoreByConversation: {
             ...state.hasMoreByConversation,
-            [conversationId]: list.length >= 50,
+            [convId]: list.length >= 50,
           },
           isLoadingOlder: false,
         };
@@ -158,58 +161,65 @@ export const useConversationStore = create<ConversationState>((set, get) => ({
   },
 
   sendMessage: async (conversationId, content) => {
-    // Add locally so the message appears immediately even if WS lags.
-    // addMessage dedupes, so a late WS event won't double it.
+    const convId = conversationId.toLowerCase();
     const message = await api.post<ConversationMessage>(
-      `/conversations/${conversationId}/messages`,
+      `/conversations/${convId}/messages`,
       { content },
     );
-    // ponytail: local append as fallback for WS MESSAGE_CREATE; remove if WS reliability improves
-    get().addMessage(message);
-    return message;
+    const normalizedMessage = { ...message, conversation_id: (message.conversation_id || convId).toLowerCase() };
+    get().addMessage(normalizedMessage);
+    return normalizedMessage;
   },
 
   addMessage: (message) => {
+    const convId = (message.conversation_id || "").toLowerCase();
+    const normalizedMessage = { ...message, conversation_id: convId };
     set((state) => {
-      const existing = state.messagesByConversation[message.conversation_id] || [];
-      if (existing.some((m) => m.id === message.id)) {
+      const existing = state.messagesByConversation[convId] || [];
+      if (existing.some((m) => m.id === normalizedMessage.id)) {
         return state;
       }
       return {
         messagesByConversation: {
           ...state.messagesByConversation,
-          [message.conversation_id]: [...existing, message]
+          [convId]: [...existing, normalizedMessage]
             .sort((a, b) => parseDate(a.created_at) - parseDate(b.created_at)),
         },
       };
     });
   },
+
   updateMessage: (message) => {
+    const convId = (message.conversation_id || "").toLowerCase();
+    const normalizedMessage = { ...message, conversation_id: convId };
     set((state) => {
-      const convMsgs = state.messagesByConversation[message.conversation_id] || [];
+      const convMsgs = state.messagesByConversation[convId] || [];
       return {
         messagesByConversation: {
           ...state.messagesByConversation,
-          [message.conversation_id]: convMsgs.map((m) => (m.id === message.id ? message : m)),
+          [convId]: convMsgs.map((m) => (m.id === normalizedMessage.id ? normalizedMessage : m)),
         },
       };
     });
   },
+
   deleteMessage: (conversationId, messageId) => {
+    const convId = conversationId.toLowerCase();
     set((state) => {
-      const convMsgs = state.messagesByConversation[conversationId] || [];
+      const convMsgs = state.messagesByConversation[convId] || [];
       return {
         messagesByConversation: {
           ...state.messagesByConversation,
-          [conversationId]: convMsgs.filter((m) => m.id !== messageId),
+          [convId]: convMsgs.filter((m) => m.id !== messageId),
         },
       };
     });
   },
 
   addReaction: (conversationId, messageId, emoji, userId) => {
+    const convId = conversationId.toLowerCase();
     set((state) => {
-      const messages = state.messagesByConversation[conversationId];
+      const messages = state.messagesByConversation[convId];
       if (!messages) return state;
 
       const newMessages = messages.map((m) => {
@@ -233,15 +243,16 @@ export const useConversationStore = create<ConversationState>((set, get) => ({
       return {
         messagesByConversation: {
           ...state.messagesByConversation,
-          [conversationId]: newMessages,
+          [convId]: newMessages,
         },
       };
     });
   },
 
   removeReaction: (conversationId, messageId, emoji, userId) => {
+    const convId = conversationId.toLowerCase();
     set((state) => {
-      const messages = state.messagesByConversation[conversationId];
+      const messages = state.messagesByConversation[convId];
       if (!messages) return state;
 
       const newMessages = messages.map((m) => {
@@ -264,7 +275,7 @@ export const useConversationStore = create<ConversationState>((set, get) => ({
       return {
         messagesByConversation: {
           ...state.messagesByConversation,
-          [conversationId]: newMessages,
+          [convId]: newMessages,
         },
       };
     });
diff --git a/web/src/stores/readStates.ts b/web/src/stores/readStates.ts
index a40b646..4c4c483 100644
--- a/web/src/stores/readStates.ts
+++ b/web/src/stores/readStates.ts
@@ -38,8 +38,9 @@ export const useReadStatesStore = create<ReadStatesState>()((set, get) => ({
   },
 
   markConvRead: (conversationId: string, messageId: string) => {
+    const convId = conversationId.toLowerCase();
     set((state) => ({
-      convStates: { ...state.convStates, [conversationId]: messageId },
+      convStates: { ...state.convStates, [convId]: messageId },
     }));
   },
 
@@ -54,8 +55,9 @@ export const useReadStatesStore = create<ReadStatesState>()((set, get) => ({
   },
 
   hasConvUnread: (conversationId: string, latestMessageId?: string): boolean => {
+    const convId = conversationId.toLowerCase();
     const state = get().convStates;
-    const lastRead = state[conversationId];
+    const lastRead = state[convId];
     if (!lastRead) return !!latestMessageId;
     if (latestMessageId && lastRead !== latestMessageId) return true;
     return false;
diff --git a/web/src/stores/ws.ts b/web/src/stores/ws.ts
index d2c717f..32c19b2 100644
--- a/web/src/stores/ws.ts
+++ b/web/src/stores/ws.ts
@@ -62,7 +62,7 @@ function extractIds(payload: UnknownPayload | undefined): { channel_id?: string;
         : null;
   if (!messageId) return null;
   if (typeof payload.channel_id === 'string') return { channel_id: payload.channel_id, message_id: messageId };
-  if (typeof payload.conversation_id === 'string') return { conversation_id: payload.conversation_id, message_id: messageId };
+  if (typeof payload.conversation_id === 'string') return { conversation_id: payload.conversation_id.toLowerCase(), message_id: messageId };
   return null;
 }
 
@@ -141,11 +141,12 @@ export const useWebSocketStore = create<WebSocketState>((set, get) => ({
           if (isRecord(payload)) {
             if (payload.conversation_id) {
               const msg = payload as unknown as ConversationMessage;
-              useConversationStore.getState().addMessage(msg);
+              const normalizedMsg = { ...msg, conversation_id: (msg.conversation_id || '').toLowerCase() };
+              useConversationStore.getState().addMessage(normalizedMsg);
               // auto-mark DM as read if this conversation is active
-              const activeConvId = useConversationStore.getState().activeConversationId;
-              if (msg.conversation_id === activeConvId && document.hasFocus()) {
-                useReadStatesStore.getState().markConvRead(msg.conversation_id, msg.id);
+              const activeConvId = (useConversationStore.getState().activeConversationId || '').toLowerCase();
+              if (normalizedMsg.conversation_id === activeConvId && document.hasFocus()) {
+                useReadStatesStore.getState().markConvRead(normalizedMsg.conversation_id, normalizedMsg.id);
               }
             } else {
               const msg = payload as unknown as Message;