Using ExpressTURN with Godot 4

Single peer connection

Godot's WebRTC API is in the official webrtc module (compiled into the engine in 4.x).

extends Node

var peer := WebRTCPeerConnection.new()

func _ready() -> void:
    peer.initialize({
        "iceServers": [
            { "urls": ["stun:stun.expressturn.com:3478"] },
            {
                "urls": [
                    "turn:relay1.expressturn.com:3478?transport=udp",
                    "turn:relay1.expressturn.com:3478?transport=tcp",
                    "turns:relay1.expressturn.com:443?transport=tcp"
                ],
                "username": "YOUR_EXPRESSTURN_USERNAME",
                "credential": "YOUR_EXPRESSTURN_PASSWORD"
            }
        ]
    })
    var ch := peer.create_data_channel("game", { "id": 1, "negotiated": true })
    peer.session_description_created.connect(_on_offer)
    peer.create_offer()

func _on_offer(type: String, sdp: String) -> void:
    peer.set_local_description(type, sdp)
    # send sdp to your signaling server

Mesh multiplayer with WebRTCMultiplayerPeer

var multiplayer_peer := WebRTCMultiplayerPeer.new()
multiplayer_peer.create_mesh(1)  # 1 = host
multiplayer.multiplayer_peer = multiplayer_peer

# When a player joins, create a connection for them and add it
func add_player(peer_id: int) -> void:
    var conn := WebRTCPeerConnection.new()
    conn.initialize({ "iceServers": ICE_SERVERS })  # same array as above
    multiplayer_peer.add_peer(conn, peer_id)
    # exchange offer/answer/ICE candidates with that peer's signaling channel

HTML5 export — Web games

Godot games exported to HTML5 use the browser's native WebRTC. Same iceServers configuration applies — Godot translates the dictionary into RTCConfiguration. The TURN-over-TLS path on port 443 is what saves your players on locked-down networks.

Common pitfalls

• "WebRTC module not enabled": In older Godot 4.x export templates the module is optional. Use the standard templates from godotengine.org or rebuild with module_webrtc_enabled=yes.
• Forgetting to call peer.poll(): WebRTCPeerConnection in Godot needs poll() called every frame. Easy to miss; connection appears stuck.
• Hard-coded credentials: Anyone can decompile your client. For published games, mint per-session credentials server-side via shared-secret HMAC.

Related: TURN for multiplayer games · Pion (Go server) recipe