Godot 4 multiplayer

The backend layer Godot deliberately does not ship.

Keep ENet, scene replication and your game loop in Godot. Add hosted player identity, persistent JSON saves, server-owned leaderboards, matchmaking, live config and a server registry without turning your game project into a backend project.

Dev BaaS: 10,000 MAU, every backend feature, unlimited projects, no credit card. Runtime is a separate capacity-gated closed alpha; admitted Dev projects get a finite evaluation allowance.

Godot 4 / GDScript real SDK surface
Crux.init_player(
  "https://crux.supercraft.host",
  PROJECT_ID, ENV_ID, PUBLISHABLE_KEY)

var auth = await Crux.login_anonymous()

await Crux.set_player_document(
  auth.player_id, "save",
  { "level": 4, "coins": 250 })
Verify before you integrate

Verify the Godot path before you create an account.

The Godot SDK and reference game are public. The API contract is inspectable, and the hosted service has a written exit path. Use those as the evaluation surface, not screenshots.

Live API status

A live check of the hosted API right now. No made-up uptime percentage and no hidden demo environment.

Check current status

Public API contract

The hosted HTTP surface is documented as OpenAPI. Inspect the wire format before choosing an SDK or writing an adapter.

Open the spec

MIT client SDKs

The JavaScript, Godot, Unity, and Roblox client SDK source is public. The hosted backend itself remains a managed proprietary service.

Inspect the SDK source

Documented exit path

Read what is exportable today and the written commitment for advance notice plus an export window if the hosted service winds down.

Read the exit guarantee

Relay Zero

A Godot 4 reference project with client/server separation, a headless authoritative server, token verification, live config, and server-owned progression.

Read the reference game
One stack, two jobs

Backend state and authoritative server lifecycle are different problems.

Crux keeps them separate so you can use only what you need. The BaaS stores durable truth; Runtime handles the short-lived Godot server process for admitted closed-alpha projects.

01

Persistent game backend

  • Guest, email and supported OAuth player identity
  • Player-scoped JSON documents for saves and progression
  • Server-owned leaderboards, inventory and currencies
  • Matchmaking, live config and server registry
  • Godot SDK plus plain HTTP when you want to stay engine-agnostic
02

Godot dedicated-server Runtime

  • Upload a Godot 4 Linux server export
  • Isolated server process with readiness lifecycle
  • Short-lived join tickets instead of handing clients secrets
  • Logs and results tied to the server session
  • No Docker or registry workflow required from the developer

Read the current Runtime contract →

Working reference

Do not evaluate this from diagrams.

Relay Zero is the open-source Godot 4 reference project already wired to Crux end to end: client/server split, authoritative headless server, token verification, versioned live config, server-owned rewards and leaderboards.

Choose by what you are actually building

NeedStart here
Accounts + saves + leaderboardGodot SDK quickstart
Compare Godot backend vendors2026 comparison
Authoritative headless serverDedicated-server guide
Managed Godot server processCrux Runtime
Unsure about scale/costPricing and limits
Shortest useful test

Make one authenticated Godot call before you commit.

Create the free project, copy the project/environment/key values into the GDScript snippet, and save a real player document. If the integration feels wrong, stop there.