Godot Multiplayer Tutorial – Real-Time Networking

Real-time multiplayer means two copies of your game agree on what happened, even though each one only hears about it after a delay. This tutorial shows a solo developer how to get a small Godot 4 scene synchronizing between two local instances. That is the right first goal. It is not a finished online game, and it does not cover matchmaking, accounts, or cheating-proof competitive play.

Godot’s multiplayer APIs have moved across major versions. Treat Godot 4’s current high-level multiplayer docs as the authority if a node or annotation name here does not match your editor.

Decide what the server owns

Before you write a socket line, decide authority. A practical solo rule is: the server owns the world, and clients send inputs, not results.

The server decides positions, hits, pickups, and scores. A client says “I pressed left” or “I asked to use the action.” The server ignores requests that are impossible, such as moving faster than the character allows or using an action on cooldown. If a client were allowed to announce “I am at this coordinate” or “that player is defeated,” anyone who edits their client could say whatever they want.

For a first test, one game instance can be the host: it is both server and a player. That is a listen server. A dedicated server process with nobody playing on it is a later split of the same idea, not a different theory.

Write down the messages you need. For a tiny shared room you might need only: join, leave, input for this tick, and a snapshot of positions. You do not need a message for every animation frame if the state already implies the animation.

Run two copies on one machine

Build a normal single-player scene first: a character that moves from local input, with collisions that already feel right. Multiplayer on top of broken movement is miserable to debug.

Add a tiny lobby UI with two buttons, Host and Join. Host creates the server peer and also connects as the local player. Join connects to an address. For the first week, the address is 127.0.0.1 and a port you chose, with the second instance started from a second run of the game. Godot’s editor can run one instance while an exported debug build, or a second run, acts as the client. Check the current docs for “multiple instances” if your version has a debug feature for this, because the menu path changes.

Godot 4’s ENet integration is the usual low-latency peer for this kind of prototype. You create an ENetMultiplayerPeer, call the host or client method documented for your version, and assign it to the tree’s multiplayer peer. When the connection succeeds, the multiplayer API assigns peer IDs. The server’s id is a fixed value in the docs. Look it up rather than memorizing a magic number from a tutorial, and compare against multiplayer.is_server().

If the second window connects and both stay open, you have a session. Nothing is replicated yet. That is still progress.

Spawn players without trusting the client

When a peer connects, the server should spawn that player’s node and record which peer owns it. Clients should not freely create networked characters. Godot 4 provides MultiplayerSpawner for this pattern. You register the scene you want to spawn, and the spawner replicates spawn and despawn to peers that are allowed to see it. Read the current spawner docs for the exact property names, including spawn limits and spawn paths.

Keep gameplay logic that must be true on the server in server-only branches. Input can be collected on every machine, but only the owning client should send that player’s inputs up. A common pattern is a function marked as a remote call that the client invokes on the server.

Godot 4 uses @rpc annotations for this. You choose who may call the function, whether it runs on the caller too, and whether the channel is reliable or unreliable. Reliable means the message arrives in order and is retried. Unreliable means it can be dropped, which is often acceptable for a stream of movement inputs that will be replaced by the next input a moment later. Chat text and “the match started” should be reliable. Check the annotation options in your version’s docs before you copy a sample, because the keyword list has changed before.

On the server, apply the input to that peer’s character using the same movement code as single player. Do not give the client a way to pass a position into that function. Pass the actions and directions, then clamp them.

Replicate state in a way you can see

MultiplayerSynchronizer can replicate chosen properties from the authority to the other peers. A start is to synchronize position and rotation, or velocity if you prefer to integrate on each side. The synchronizer’s replication interval is a setting you should experiment with. Faster updates look smoother and cost more bandwidth. For a local prototype, bandwidth is not your limit. For a real network, it will be.

Local play on localhost hides lag. Once the basic sync works, add a way to simulate delay, or simply test on two machines on your home network. If you only ever test on 127.0.0.1, you will not notice that your character snaps or that inputs feel late.

A straightforward interpolation approach for a beginner is: the remote puppet shows the latest received state, and you ease the drawn position toward it instead of teleporting every update. Do this only for puppets, not for the local predicted character, or your own controls will feel muddy. Prediction, simulating ahead and reconciling when the server disagrees, is the next step after puppets look acceptable. It is easy to get wrong. Ship a slightly delayed but consistent puppet before you build a prediction system you cannot debug.

Validate the few actions that matter

Add one interaction, not a combat system. A button that picks up a coin is enough.

The client sends “I want to pick up the coin near me.” The server checks distance, checks that the coin still exists, removes it, and updates the score. Then it replicates the coin’s disappearance. If two players request it on the same tick, one check fails and that player does not get the point. That single rule is the heart of server authority.

Reject inputs that arrive too often. A tiny cooldown on the server, even a few tenths of a second for a non-movement action, stops a modified client from flooding the function. You do not need a perfect anti-cheat design to avoid trusting the client by default.

Keep score and inventory on the server. If a user interface needs to show them, replicate the final values. Do not let the client add points locally and hope the server agrees.

What to leave for later

Connecting across the public internet means firewalls, NAT, and an address people can reach. A listen server on your laptop may work on a local network and fail for a friend elsewhere. Port forwarding, relays, and hosted servers are separate tasks. Read Godot’s current networking docs and your host’s docs when you get there. Do not buy infrastructure for a prototype that still breaks on localhost.

Also later: animation parameters that match movement, interest management so you do not sync the whole world, reconnecting after a drop, and saving characters. Each of those assumes the host, spawn, input, and authority loop already works.

When two windows on one computer show two characters, each driven only by its own keyboard, and a coin disappears for both only after the server allows the pickup, stop and save the project. That slice is a real multiplayer foundation. Growing it into a commercial online game is a different, much longer effort.