diff --git a/demo/api/conversations/controllers/conversationsController.ts b/demo/api/conversations/controllers/conversationsController.ts
new file mode 100644
index 00000000..b876ec17
--- /dev/null
+++ b/demo/api/conversations/controllers/conversationsController.ts
@@ -0,0 +1,12 @@
+import { Request, Response } from 'express';
+import { createConversation, getConversation } from '../inMemoryDb';
+
+export const handleCreateConversation = (req: Request, res: Response) => {
+  const conversationId = req.params.conversationId;
+  res.json(createConversation(conversationId));
+};
+
+export const handleGetConversation = (req: Request, res: Response) => {
+  const conversationId = req.params.conversationId;
+  res.json(getConversation(conversationId));
+};
diff --git a/demo/api/conversations/controllers/messagesController.ts b/demo/api/conversations/controllers/messagesController.ts
new file mode 100644
index 00000000..c063280a
--- /dev/null
+++ b/demo/api/conversations/controllers/messagesController.ts
@@ -0,0 +1,62 @@
+import * as Ably from 'ably/promises';
+import { Request, Response } from 'express';
+import { createMessage, deleteMessage, editMessage, findMessages } from '../inMemoryDb';
+
+export const handleCreateMessage = (req: Request, res: Response) => {
+  const conversationId = req.params.conversationId;
+  const ablyToken = req.headers.authorization.split(' ')[1];
+
+  const message = createMessage({
+    ...JSON.parse(req.body),
+    client_id: req.headers['ably-clientid'] as string,
+    conversation_id: conversationId,
+  });
+
+  const client = new Ably.Rest(ablyToken);
+
+  client.channels.get(`conversations:${conversationId}`).publish('message.created', message);
+
+  res.json({ id: message.id });
+
+  res.status(201).end();
+};
+
+export const handleQueryMessages = (req: Request, res: Response) => {
+  const conversationId = req.params.conversationId;
+  res.json(findMessages(conversationId, req.headers['ably-clientid'] as string));
+};
+
+export const handleEditMessages = (req: Request, res: Response) => {
+  const conversationId = req.params.conversationId;
+  const ablyToken = req.headers.authorization.split(' ')[1];
+
+  const message = editMessage({
+    id: req.params.messageId,
+    conversation_id: conversationId,
+    ...JSON.parse(req.body),
+  });
+
+  const client = new Ably.Rest(ablyToken);
+
+  client.channels.get(`conversations:${conversationId}`).publish('message.updated', message);
+
+  res.json({ id: message.id });
+
+  res.status(201).end();
+};
+
+export const handleDeleteMessages = (req: Request, res: Response) => {
+  const conversationId = req.params.conversationId;
+  const ablyToken = req.headers.authorization.split(' ')[1];
+
+  const message = deleteMessage({
+    id: req.params.messageId,
+    conversation_id: conversationId,
+  });
+
+  const client = new Ably.Rest(ablyToken);
+
+  client.channels.get(`conversations:${conversationId}`).publish('message.deleted', message);
+
+  res.status(201).end();
+};
diff --git a/demo/api/conversations/controllers/reactionsController.ts b/demo/api/conversations/controllers/reactionsController.ts
new file mode 100644
index 00000000..f2ca6b8c
--- /dev/null
+++ b/demo/api/conversations/controllers/reactionsController.ts
@@ -0,0 +1,34 @@
+import { Request, Response } from 'express';
+import * as Ably from 'ably/promises';
+import { addReaction, deleteReaction } from '../inMemoryDb';
+
+export const handleAddReaction = (req: Request, res: Response) => {
+  const conversationId = req.params.conversationId;
+  const ablyToken = req.headers.authorization.split(' ')[1];
+
+  const reaction = addReaction({
+    message_id: req.params.messageId,
+    conversation_id: conversationId,
+    client_id: req.headers['ably-clientid'] as string,
+    ...JSON.parse(req.body),
+  });
+
+  const client = new Ably.Rest(ablyToken);
+
+  client.channels.get(`conversations:${conversationId}`).publish('reaction.added', reaction);
+
+  res.status(201).end();
+};
+
+export const handleDeleteReaction = (req: Request, res: Response) => {
+  const reactionId = req.params.reactionId;
+  const ablyToken = req.headers.authorization.split(' ')[1];
+
+  const reaction = deleteReaction(reactionId);
+
+  const client = new Ably.Rest(ablyToken);
+
+  client.channels.get(`conversations:${reaction.conversation_id}`).publish('reaction.deleted', reaction);
+
+  res.status(201).end();
+};
diff --git a/demo/api/conversations/inMemoryDb.ts b/demo/api/conversations/inMemoryDb.ts
new file mode 100644
index 00000000..b1295606
--- /dev/null
+++ b/demo/api/conversations/inMemoryDb.ts
@@ -0,0 +1,139 @@
+import { ulid } from 'ulidx';
+import exp = require('constants');
+
+export interface Conversation {
+  id: string;
+  application_id: string;
+  ttl: number | null;
+  created_at: number;
+}
+
+export interface Message {
+  id: string;
+  client_id: string;
+  conversation_id: string;
+  content: string;
+  reactions: {
+    counts: Record<string, number>;
+    latest: Reaction[];
+    mine: Reaction[];
+  };
+  created_at: number;
+  updated_at: number | null;
+  deleted_at: number | null;
+}
+
+export interface Reaction {
+  id: string;
+  message_id: string;
+  conversation_id: string;
+  type: string;
+  client_id: string;
+  updated_at: number | null;
+  deleted_at: number | null;
+}
+
+const conversations: Conversation[] = [];
+const conversationIdToMessages: Record<string, Message[]> = {};
+const reactions: Reaction[] = [];
+
+export const createConversation = (id: string): Conversation => {
+  const existing = conversations.find((conv) => conv.id === id);
+  if (existing) return existing;
+  const conversation = {
+    id,
+    application_id: 'demo',
+    ttl: null,
+    created_at: Date.now(),
+  };
+  conversationIdToMessages[id] = [];
+  conversations.push(conversation);
+  return conversation;
+};
+
+createConversation('conversation1');
+
+export const getConversation = (id: string): Conversation => {
+  return conversations.find((conv) => conv.id === id);
+};
+
+export const findMessages = (conversationId: string, clientId: string) =>
+  enrichMessagesWithReactions(conversationIdToMessages[conversationId], clientId);
+
+export const createMessage = (message: Pick<Message, 'client_id' | 'conversation_id' | 'content'>) => {
+  const created: Message = {
+    ...message,
+    id: ulid(),
+    reactions: {
+      counts: {},
+      latest: [],
+      mine: [],
+    },
+    created_at: Date.now(),
+    updated_at: null,
+    deleted_at: null,
+  };
+  conversationIdToMessages[created.conversation_id].push(created);
+  return created;
+};
+
+export const editMessage = (message: Pick<Message, 'id' | 'conversation_id' | 'content'>) => {
+  const edited = conversationIdToMessages[message.conversation_id].find(({ id }) => message.id === id);
+  edited.content = message.content;
+  return edited;
+};
+
+export const deleteMessage = (message: Pick<Message, 'id' | 'conversation_id'>) => {
+  const deletedIndex = conversationIdToMessages[message.conversation_id].findIndex(({ id }) => message.id === id);
+  const deleted = conversationIdToMessages[message.conversation_id][deletedIndex];
+  conversationIdToMessages[message.conversation_id].splice(deletedIndex, 1);
+  return deleted;
+};
+
+export const addReaction = (
+  reaction: Pick<Reaction, 'id' | 'message_id' | 'type' | 'client_id' | 'conversation_id'>,
+) => {
+  const created: Reaction = {
+    ...reaction,
+    id: ulid(),
+    updated_at: null,
+    deleted_at: null,
+  };
+  reactions.push(created);
+  return created;
+};
+
+export const deleteReaction = (reactionId: string) => {
+  const deletedIndex = reactions.findIndex((reaction) => reaction.id === reactionId);
+  const deleted = reactions[deletedIndex];
+  reactions.splice(deletedIndex, 1);
+  return deleted;
+};
+
+const enrichMessageWithReactions = (message: Message, clientId: string): Message => {
+  const messageReactions = reactions.filter((reaction) => reaction.message_id === message.id);
+  const mine = messageReactions.filter((reaction) => reaction.client_id === clientId);
+  const counts = messageReactions.reduce(
+    (acc, reaction) => {
+      if (acc[reaction.type]) {
+        acc[reaction.type]++;
+      } else {
+        acc[reaction.type] = 1;
+      }
+      return acc;
+    },
+    {} as Record<string, number>,
+  );
+  return {
+    ...message,
+    reactions: {
+      counts,
+      latest: messageReactions,
+      mine,
+    },
+  };
+};
+
+const enrichMessagesWithReactions = (messages: Message[], clientId: string) => {
+  return messages.map((message) => enrichMessageWithReactions(message, clientId));
+};
diff --git a/demo/api/conversations/index.ts b/demo/api/conversations/index.ts
index f0da53a2..4aa3287f 100644
--- a/demo/api/conversations/index.ts
+++ b/demo/api/conversations/index.ts
@@ -1,50 +1,12 @@
 import * as dotenv from 'dotenv';
-import * as Ably from 'ably/promises';
-import { ulid } from 'ulidx';
-import express, { Router } from 'express';
+import express from 'express';
 import serverless from 'serverless-http';
+import { router } from './routes';
 
 dotenv.config();
 
-const messages = [];
-
 const api = express();
 
-const router = Router();
-router.post('/conversations/:conversationId/messages', (req, res) => {
-  const conversationId = req.params.conversationId;
-  const ablyToken = req.headers.authorization.split(' ')[1];
-
-  const message = {
-    id: ulid(),
-    ...JSON.parse(req.body),
-    client_id: req.headers['ably-clientid'],
-    conversation_id: conversationId,
-    reactions: {
-      counts: {},
-      latest: [],
-      mine: [],
-    },
-    created_at: Date.now(),
-    updated_at: null,
-    deleted_at: null,
-  };
-
-  messages.push(message);
-
-  const client = new Ably.Rest(ablyToken);
-
-  client.channels.get(`conversations:${conversationId}`).publish('message.created', message);
-
-  res.json({ id: message.id });
-
-  res.status(201).end();
-});
-
-router.get('/conversations/:conversationId/messages', (req, res) => {
-  res.json(messages);
-});
-
 api.use('/api/conversations/v1', router);
 
 export const handler = serverless(api);
diff --git a/demo/api/conversations/routes.ts b/demo/api/conversations/routes.ts
new file mode 100644
index 00000000..44ca80fe
--- /dev/null
+++ b/demo/api/conversations/routes.ts
@@ -0,0 +1,35 @@
+import { Router } from 'express';
+import {
+  handleCreateMessage,
+  handleDeleteMessages,
+  handleEditMessages,
+  handleQueryMessages,
+} from './controllers/messagesController';
+import { handleCreateConversation, handleGetConversation } from './controllers/conversationsController';
+import { handleAddReaction, handleDeleteReaction } from './controllers/reactionsController';
+
+const router = Router();
+
+// Conversations
+
+router.post('/conversations/:conversationId', handleCreateConversation);
+
+router.get('/conversations/:conversationId', handleGetConversation);
+
+// Messages
+
+router.post('/conversations/:conversationId/messages', handleCreateMessage);
+
+router.get('/conversations/:conversationId/messages', handleQueryMessages);
+
+router.post('/conversations/:conversationId/messages/:messageId', handleEditMessages);
+
+router.delete('/conversations/:conversationId/messages/:messageId', handleDeleteMessages);
+
+// Reactions
+
+router.post('/conversations/:conversationId/messages/:messageId/reactions', handleAddReaction);
+
+router.delete('/reactions/:reactionId', handleDeleteReaction);
+
+export { router };
diff --git a/demo/src/containers/ConversationContext/ConversationProvider.tsx b/demo/src/containers/ConversationContext/ConversationProvider.tsx
index 773beccb..55903314 100644
--- a/demo/src/containers/ConversationContext/ConversationProvider.tsx
+++ b/demo/src/containers/ConversationContext/ConversationProvider.tsx
@@ -15,5 +15,6 @@ export const ConversationProvider: FC<ConversationProviderProps> = ({ client, co
     }),
     [client, conversationId],
   );
+
   return <ConversationContext.Provider value={value}>{children}</ConversationContext.Provider>;
 };