# Step-by-Step: Your First Netcode Implementation in Unity ![](https://cdn.hashnode.com/uploads/covers/685a6d69d4d0ea366852534c/6a18425d-ca9a-4091-860e-8eaf71497e1a.png align="center") Adding multiplayer to a Unity project can feel complex at first, but the core networking flow becomes much easier once you build a small working example. In this **Unity netcode tutorial**, we’ll create a simple host-and-client setup using Netcode for GameObjects, spawn networked players, synchronize movement, and test the result locally. Understanding these fundamentals is also an important part of modern [Unity game development](https://sdlccorp.com/services/games/unity-game-development-company/), especially when building real-time multiplayer experiences. Our basic architecture will look like this: ```text Player 1 ↓ Host ↓ NetworkManager ↓ Unity Transport ↓ Client ↓ Player 2 ``` * * * ## Step 1: Install Netcode for GameObjects Create a Unity project and open: **Window → Package Management → Package Manager** Install: ```text Netcode for GameObjects ``` You’ll also use Unity Transport for the underlying network communication. The basic stack is: ```text Netcode for GameObjects + Unity Transport ``` For a first implementation, this gives you everything needed to create a local client-server multiplayer session. * * * ## Step 2: Add the NetworkManager Create an empty GameObject named: ```text NetworkManager ``` Add these components: * `NetworkManager` * `UnityTransport` The NetworkManager is responsible for managing the multiplayer session. It handles tasks such as: ```text Starting the host Connecting clients Spawning players Network configuration Managing network prefabs ``` For this tutorial, we’ll use a standard client-server setup. * * * ## Step 3: Create Host and Client Buttons Create a simple Canvas with two buttons: ```text Start Host Start Client ``` Then add this script: ```csharp using Unity.Netcode; using UnityEngine; public class NetworkLauncher : MonoBehaviour { public void StartHost() { NetworkManager.Singleton.StartHost(); } public void StartClient() { NetworkManager.Singleton.StartClient(); } } ``` Connect each button to its matching method. The flow becomes: ```text Start Host ↓ Server + Local Client Start Client ↓ Connect to Host ``` The host acts as both the server and a participating client. * * * ## Step 4: Create a Networked Player Create a simple player using a Cube, Capsule, or character model. Add: ```text NetworkObject NetworkTransform NetworkPlayer script ``` Then convert the object into a prefab. Your hierarchy might look like: ```text Player ├── NetworkObject ├── NetworkTransform └── NetworkPlayer ``` The `NetworkObject` gives Netcode a way to identify and manage the object across connected clients. * * * ## Step 5: Assign the Player Prefab Select your **NetworkManager**. Find the: ```text Player Prefab ``` field and assign your networked Player prefab. Now, whenever a client joins successfully, Netcode can create a player object automatically. Instead of manually placing multiple players into the scene, the networking system handles player creation for you. * * * ## Step 6: Add Basic Player Movement Create a script named: ```text NetworkPlayer.cs ``` Example: ```csharp using Unity.Netcode; using UnityEngine; public class NetworkPlayer : NetworkBehaviour { [SerializeField] private float speed = 4f; private void Update() { if (!IsOwner) return; float horizontal = Input.GetAxisRaw("Horizontal"); float vertical = Input.GetAxisRaw("Vertical"); Vector2 input = new Vector2(horizontal, vertical); if (input.sqrMagnitude > 0) { MoveRpc(input.normalized); } } [Rpc(SendTo.Server)] private void MoveRpc(Vector2 input) { Vector3 movement = new Vector3( input.x, 0, input.y ); transform.position += movement * speed * Time.deltaTime; } } ``` The important check is: ```csharp if (!IsOwner) return; ``` This ensures that each client controls only its own player. Conceptually: ```text Client 1 → Player 1 Client 2 → Player 2 ``` Without ownership checks, one client could unintentionally control other players. * * * ## Step 7: Understand the RPC This method: ```csharp [Rpc(SendTo.Server)] private void MoveRpc(Vector2 input) ``` is an RPC, or Remote Procedure Call. The flow is: ```text Client Input ↓ RPC ↓ Server ↓ Server Updates Player ``` The client sends its movement request to the server, and the server applies the movement. For a beginner project, this is a useful way to understand client-server communication. For larger competitive games, this foundation usually grows into a more complete [server-authoritative multiplayer architecture](https://sdlccorp.com/post/how-to-develop-a-game-like-free-fire/) involving dedicated servers, matchmaking, prediction, validation, and latency management. * * * ## Step 8: Synchronize Player Movement The server now changes the player's position. Other clients also need to see that change. That is where: ```text NetworkTransform ``` helps. It synchronizes position, rotation, and other Transform properties across networked instances. The full flow becomes: ```text Player Input ↓ MoveRpc ↓ Server Moves Player ↓ NetworkTransform ↓ Other Clients See Movement ``` At this point, you already have the foundation of server-controlled multiplayer movement. * * * ## Step 9: Add a NetworkVariable Not every networked value should be sent as an RPC. Suppose you want to synchronize a player's score. You can use: ```csharp public NetworkVariable Score = new NetworkVariable(0); ``` The server can update it: ```csharp if (IsServer) { Score.Value += 1; } ``` NetworkVariables are useful for persistent synchronized values such as: ```text Health Score Ammo Team Ready status Match state ``` A simple rule is: ```text RPC → Something happened NetworkVariable → Something has a state ``` For example: ```text Player fired weapon → RPC Player health = 75 → NetworkVariable ``` * * * ## Step 10: Test Two Players Locally For multiplayer development, test with at least two running instances. Start one instance as: ```text Host ``` and another as: ```text Client ``` You should see both players on each instance: ```text Host ├── Player 1 └── Player 2 Client ├── Player 1 └── Player 2 ``` Move Player 1 and verify that only Player 1 responds. Then move Player 2 and confirm the same behavior. * * * ## Step 11: Test the Important Scenarios Before adding more multiplayer features, validate the basic networking behavior. ### Host Starts Expected: ```text Host session starts Player 1 spawns ``` ### Client Connects Expected: ```text Player 2 joins Both players appear ``` ### Player Ownership Move one player. Expected: ```text Only the owner controls that player ``` ### State Synchronization Change a NetworkVariable. Expected: ```text The updated value appears on connected clients ``` These checks help confirm that the fundamentals are working correctly before you expand the project. * * * ## RPC vs NetworkVariable Choosing the correct synchronization method is important. ### Use RPCs for events Examples: ```text Shoot Open door Press button Interact Play effect ``` ### Use NetworkVariables for state Examples: ```text Health Score Team Ammo Match status ``` Using each for its intended purpose keeps networking code cleaner and easier to maintain. * * * ## Common Unity Netcode Mistakes ### Forgetting the NetworkObject Any GameObject that needs network synchronization should generally include a `NetworkObject`. ### Ignoring Ownership Always check ownership before processing local player input. ```csharp if (!IsOwner) return; ``` ### Trusting the Client Too Much For important gameplay actions, validate them on the server. ### Synchronizing Everything Every synchronized value consumes network bandwidth. Only synchronize data that other clients actually need. ### Testing With One Player A multiplayer feature can appear correct with one instance and fail as soon as another client joins. ### Starting With Matchmaking Too Early First prove the core networking flow. Then add: ```text Relay Lobby Matchmaking Dedicated Servers Authentication ``` * * * ## Your First Netcode Architecture At this stage, your multiplayer setup looks like: ```text NetworkManager │ Unity Transport │ ┌───────────┴───────────┐ ↓ ↓ Host Client │ │ └───────────┬───────────┘ ↓ NetworkObjects ↓ NetworkBehaviour ┌─────┴─────┐ ↓ ↓ RPC NetworkVariable ↓ ↓ Events State ``` This simple structure is the foundation for much larger multiplayer games. * * * ## What Should You Build Next? Once local multiplayer works reliably, expand gradually: ```text Phase 1: Connection Phase 2: Movement Phase 3: Health & Score Phase 4: Shooting Phase 5: Player Spawning Phase 6: Relay Phase 7: Lobby Phase 8: Matchmaking Phase 9: Dedicated Servers ``` Building one system at a time keeps your networking architecture easier to test and debug. * * * ## Final Thoughts Your first multiplayer implementation does not need to include complex matchmaking, prediction, dedicated servers, or advanced lag compensation. Start with four concepts: **Connect → Own → Communicate → Synchronize** A successful first **Unity netcode tutorial** should prove that: ```text Two players can connect ↓ Each controls their own object ↓ Gameplay requests reach the server ↓ State is synchronized ``` Once this works, you have a strong foundation for combat, lobbies, Relay, matchmaking, prediction, and dedicated multiplayer servers. Keep the first implementation simple, understand who owns each object, and expand the multiplayer architecture one system at a time.