How to Build a Multiplayer Game Lobby with JavaScript and Firebase

 

Ever played a multiplayer game and wondered, How does this lobby even work? That virtual waiting room where participants converse and prepare before the game? You can make or break your players' experience with a smooth gaming lobby, where community, teams, and enthusiasm start.

The good news? You do not need a big backend or server engineers to construct one. JavaScript and Firebase make real-time multiplayer lobby creation easy. To get your players connected and ready to fight, I will walk you through setting up a basic gaming lobby. Come on!

 

Why Use Firebase for a Game Lobby?

Why choose Firebase? Consider Firebase your backstage crew, it handles real-time magic as you play. Firebase's Realtime Database syncs data quickly across all players' devices. Player joins? Everyone notices. Player goes? Instantly updated.

Without servers or WebSocket logic, it manages significant backend issues including expanding connections and keeping data in real time. You do not require backend frameworks or hosting because you are using JavaScript. Everything works out of the box.

Core Features of a Game Lobby

Let's take a look at what a simple game lobby does before we start making. It needs to let players:

• Create a room: Make a room because your friends might want to play together.
• Join an existing room: Choose a room, jump in, and look around to see who else is there.
• See who's online: No one likes to wait by themselves!
• Get real-time updates: If someone joins or quits, everyone knows right away.
• Optional extras: You can add extras like chat, ready-up state, or even map voting if you want to.

These are the basics that every multiplayer lobby needs, whether it is for a casual shooter or a strategy game.

Setting Up Firebase

Let's get Firebase ready, so roll up your sleeves.

Step 1: Create a Firebase project

Make a new project in Firebase Console. Simple.

Step 2: Enable the Realtime Database

Simply go to Build > Realtime Database, click on Create Database, and make the rules public for testing:

{
  "rules": {
    ".read": true,
   ".write": true
  }
}

Don't worry, we'll lock these down later.

Step 3: Add Firebase to your web app

In your HTML, add the Firebase scripts:

<script src="https://www.gstatic.com/firebasejs/9.0.0/firebase-app.js"></script>
<script src="https://www.gstatic.com/firebasejs/9.0.0/firebase-database.js"></script>

Step 4: Initialize Firebase in your JavaScript:

const firebaseConfig = {
  apiKey: "YOUR_API_KEY",
  authDomain: "YOUR_PROJECT.firebaseapp.com",
  databaseURL: "https://YOUR_PROJECT.firebaseio.com",
  projectId: "YOUR_PROJECT",
};

firebase.initializeApp(firebaseConfig);
const database = firebase.database();

And just like that, you're ready to build your lobby!

Building the Lobby with JavaScript

Now comes the fun part: bringing life to your lobby.

Create and Join Rooms

Let's start by making a simple form that people can use to make or join rooms:

<input type="text" id="roomName" placeholder="Room name">
<button onclick="createRoom()">Create Room</button>
<button onclick="joinRoom()">Join Room</button>

In your JS:

function createRoom() {
  const room = document.getElementById("roomName").value;
 database.ref("rooms/" + room).set({
    createdAt: Date.now()
  });
  joinRoom();
}

function joinRoom() {
  const room = document.getElementById("roomName").value;
  const playerId = "player_" + Date.now();
  const playerRef = database.ref("rooms/" + room + "/players/" + playerId);
 
  playerRef.set({ joinedAt: Date.now() });
 
  // Remove player if they disconnect
 playerRef.onDisconnect().remove();
 
 listenForPlayers(room);
}

Track Who's Online

Let's now show a list of the people in the room. We will check the players node for changes:

function listenForPlayers(room) {
  const playerList = document.getElementById("players");
 database.ref("rooms/" + room + "/players").on("value", (snapshot) => {
   playerList.innerHTML = "";
   snapshot.forEach((child) => {
      const li = document.createElement("li");
      li.textContent = child.key;
     playerList.appendChild(li);
    });
  });
}

Add this to your HTML:

<ul id="players"></ul>

Boom! As players join or leave, the list refreshes live for everyone.

Add Ready Status or Chat (Optional)

Do you want to seem fancy? For this you can set up a flag that says "ready" or a chat box. Run this code to get the person ready: 

playerRef.update({ ready: true });

Or, make a messages node and send chat messages through it. It works the same way, but it is more fun.

Handling Edge Cases & Tips

While you test, consider about these things:

• Use onDisconnect() to end the link for people who close the tab.
• Use more than one tab to test real-time sync.
• Before going live, restrict database changes to permitted users.
• Set limits on the size of the rooms or give people who are not playing timeouts.

Conclusion

That's it! You now have your own lobby for playing multiplayers games online. You made a JavaScript and Firebase system that lets people make rooms, join them, check who is online, and get updates in real time without any problems on the backend.

This is just the beginning. To make it bigger, you can add chat, game types, matching, or built-in game logic. When you see how well it works, you will wish you were more prompt.

Open your computer, ask your friends to join, and start making your dream multiplayer game. The lobby is ready for you!