diff --git a/src/tic-tac-toe/src/app.ts b/src/tic-tac-toe/src/app.ts
new file mode 100644
index 0000000..ca5fa57
--- /dev/null
+++ b/src/tic-tac-toe/src/app.ts
@@ -0,0 +1,198 @@
+import fastify, { FastifyInstance, FastifyPluginAsync } from 'fastify';
+// TODO: Import Fastify formbody
+// TODO: Import Fastify multipart
+// TODO: Import shared database
+// TODO: Import shared auth
+// TODO: Import shared swagger
+// TODO: Import shared utils
+// TODO: Import socketio
+
+// @brief ???
+declare const __SERVICE_NAME: string;
+
+// TODO: Import the plugins defined for this microservice
+// TODO: Import the routes defined for this microservice
+
+// @brief The microservice app (as a plugin for Fastify), kinda like a main function I guess ???
+// @param fastify
+// @param opts
+export const app: FastifyPluginAsync = async (fastify, opts): Promise<void> => {
+	// Register all the fastify plugins that this app will use
+
+	// Once it is done:
+	fastify.ready((err) => {
+		if (err) {
+			throw err;
+		}
+		// TODO: Supposedly, something should be there I guess
+	});
+};
+// Export it as the default for this file.
+export default app;
+
+// TODO: Understand what is this for in /src/chat/src/app.ts
+// declare module 'fastify' {
+// 	interface FastifyInstance {
+// 		io: Server<{
+// 			hello: (message: string) => string;
+// 			MsgObjectServer: (data: { message: ClientMessage }) => void;
+// 			message: (msg: string) => void;
+// 			testend: (sock_id_client: string) => void;
+// 		}>;
+// 	}
+// }
+
+// TODO: Same for this, also in /src/chat/src/app.ts
+// async function onReady(fastify: FastifyInstance) {
+// 	function connectedUser(io?: Server, target?: string): number {
+// 		let count = 0;
+// 		const seen = new Set<string>();
+// 		// <- only log/count unique usernames
+
+// 		for (const [socketId, username] of clientChat) {
+// 			// Basic sanity checks
+// 			if (typeof socketId !== 'string' || socketId.length === 0) {
+// 				clientChat.delete(socketId);
+// 				continue;
+// 			}
+// 			if (typeof username !== 'string' || username.length === 0) {
+// 				clientChat.delete(socketId);
+// 				continue;
+// 			}
+
+// 			// If we have the io instance, attempt to validate the socket is still connected
+// 			if (io && typeof io.sockets?.sockets?.get === 'function') {
+// 				const s = io.sockets.sockets.get(socketId) as
+// 					| Socket
+// 					| undefined;
+// 				// If socket not found or disconnected, remove from map and skip
+// 				if (!s || s.disconnected) {
+// 					clientChat.delete(socketId);
+// 					continue;
+// 				}
+
+// 				// Skip duplicates (DO NOT delete them — just don't count)
+// 				if (seen.has(username)) {
+// 					continue;
+// 				}
+// 				// socket exists and is connected
+// 				seen.add(username);
+// 				count++;
+// 				// console.log(color.green,"count: ", count);
+// 				console.log(color.yellow, 'Client:', color.reset, username);
+
+// 				const targetSocketId = target;
+// 				io.to(targetSocketId!).emit('listObj', username);
+
+// 				console.log(
+// 					color.yellow,
+// 					'Chat Socket ID:',
+// 					color.reset,
+// 					socketId,
+// 				);
+// 				continue;
+// 			}
+
+// 			// If no io provided, assume entries in the map are valid and count them.
+// 			count++;
+// 			console.log(
+// 				color.red,
+// 				'Client (unverified):',
+// 				color.reset,
+// 				username,
+// 			);
+// 			console.log(
+// 				color.red,
+// 				'Chat Socket ID (unverified):',
+// 				color.reset,
+// 				socketId,
+// 			);
+// 		}
+
+// 		return count;
+// 	}
+
+// 	function broadcast(data: ClientMessage, sender?: string) {
+// 		fastify.io.fetchSockets().then((sockets) => {
+// 			for (const s of sockets) {
+// 				if (s.id !== sender) {
+// 					// Send REAL JSON object
+// 					const clientName = clientChat.get(s.id) || null;
+// 					if (clientName !== null) {
+// 						s.emit('MsgObjectServer', { message: data });
+// 					}
+// 					console.log(' Target window socket ID:', s.id);
+// 					console.log(' Target window ID:', [...s.rooms]);
+// 					console.log(' Sender window ID:', sender ? sender : 'none');
+// 				}
+// 			}
+// 		});
+// 	}
+
+// 	fastify.io.on('connection', (socket: Socket) => {
+// 		socket.on('message', (message: string) => {
+// 			console.info(
+// 				color.blue,
+// 				'Socket connected!',
+// 				color.reset,
+// 				socket.id,
+// 			);
+// 			console.log(
+// 				color.blue,
+// 				'Received message from client',
+// 				color.reset,
+// 				message,
+// 			);
+
+// 			const obj: ClientMessage = JSON.parse(message) as ClientMessage;
+// 			clientChat.set(socket.id, obj.user);
+// 			console.log(
+// 				color.green,
+// 				'Message from client',
+// 				color.reset,
+// 				`Sender: login name: "${obj.user}" - windowID "${obj.SenderWindowID}" - text message: "${obj.text}"`,
+// 			);
+// 			// Send object directly — DO NOT wrap it in a string
+// 			broadcast(obj, obj.SenderWindowID);
+// 			console.log(
+// 				color.red,
+// 				'connected in the Chat :',
+// 				connectedUser(fastify.io),
+// 				color.reset,
+// 			);
+// 		});
+
+// 		socket.on('testend', (sock_id_cl: string) => {
+// 			console.log('testend received from client socket id:', sock_id_cl);
+// 		});
+
+// 		socket.on('list', () => {
+// 			console.log(color.red, 'list activated', color.reset, socket.id);
+// 			connectedUser(fastify.io, socket.id);
+// 		});
+
+// 		socket.on('disconnecting', (reason) => {
+// 			const clientName = clientChat.get(socket.id) || null;
+// 			console.log(
+// 				color.green,
+// 				`Client disconnecting: ${clientName} (${socket.id}) reason:`,
+// 				reason,
+// 			);
+// 			if (reason === 'transport error') return;
+
+// 			if (clientName !== null) {
+// 				const obj = {
+// 					type: 'chat',
+// 					user: clientName,
+// 					token: '',
+// 					text: 'LEFT the chat',
+// 					timestamp: Date.now(),
+// 					SenderWindowID: socket.id,
+// 				};
+
+// 				broadcast(obj, obj.SenderWindowID);
+// 				//   clientChat.delete(obj.user);
+// 			}
+// 		});
+// 	});
+// }
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