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Rust + Bevy

Ghost Chase 1v1 is a real-time multiplayer duel built in Rust with Bevy that wires up the full GameFlow integration: a dedicated game server per match, queue matchmaking, and skill rating. A thin backend holds the API key; the desktop client talks only to that backend.

Ghost Chase 1v1 title screen

Prerequisites​

  • A GameFlow account
  • Rust (the repo pins the toolchain via rust-toolchain.toml, so plain cargo uses the right version)
  • cloudflared to expose your backend during testing
  • Linux only: the desktop client needs a GPU and a windowing stack. On Debian/Ubuntu, install the runtime libraries first: 
    sudo apt install -y libxkbcommon-x11-0 libvulkan1 mesa-vulkan-drivers

Step 1: Clone the Repository​

git clone https://github.com/GameFlowGG/gameflow-bevy-multiplayer-example
cd gameflow-bevy-multiplayer-example

Step 2: Architecture​

Three processes plus a pure-logic crate they share. Only the backend ever holds the API key.

CrateWhat it isHolds the API key?
clientThe desktop app. Renders, predicts its own runner, talks only to your backend.No
backendA thin axum server you host. The only holder of the GameFlow API key; it brokers every GameFlow call for the client and the server.Yes
serverThe headless Bevy authority. GameFlow builds it from your uploaded zip and allocates one per match.No
sharedThe whole game as plain Rust: maze, movement, ghosts, pellets, scoring, wire protocol. No Bevy, no networking.n/a

The game server never talks to GameFlow directly. At game over it reports the result back through the backend, which owns the key and forwards it to skill rating.

Step 3: Build the Server Zip​

GameFlow builds the server from an uploaded zip. A Dockerfile at the root of the zip wins over any engine template, which is the whole reason a Rust server needs no platform change.

scripts/package-server.sh          # writes ghostchase-server.zip

Step 4: Create a Game on GameFlow​

  1. Create a new game on the GameFlow Dashboard and generate an org-scoped API key (Settings → API keys). It goes only in the backend's .env.
  2. Set Memory to 512MB and vCPU to 0.5 cores.
  3. Set the Port to 2567, protocol UDP (the server uses renet/netcode over UDP).
  4. Enable the us-east region.

Step 5: Upload the Build​

Upload ghostchase-server.zip in the builds section and wait until it reaches success and is marked current.

Step 6: Matchmaker and Skill Model​

Publish a matchmaker for game mode 1v1 with this flow:

Ticket Input → Skill Model → Skill Rule → Expansion Rule → Team Composition → Output
  • Team Composition: 2 teams of 1 player.
  • Create an org-scoped Skill Model (2 teams × 1 player) and select it on the Skill Model node.
  • Click Publish.

Step 7: Host the Backend and Expose It​

The backend holds the API key and must be reachable by your players and by the game server. Fill crates/backend/.env:

  • GAMEFLOW_API_URL, GAMEFLOW_API_KEY, GAMEFLOW_GAME_ID
  • GAMEFLOW_GAME_MODE=1v1, GAMEFLOW_REGION=us-east
  • GAME_BACKEND_API_TOKEN (a shared secret the game server presents when reporting results)
  • JWT_SECRET, PORT (default 8080)

Because the game server runs on GameFlow, it reaches your backend over the public internet. During testing, expose your backend with a Cloudflare quick tunnel:

set -a && . crates/backend/.env && set +a
cargo run -p ghostchase-backend                # listens on :8080

# in another terminal
cloudflared tunnel --url http://localhost:8080  # prints a public https URL

Give the game server those values in the dashboard: open your game in the GameFlow Dashboard, edit it, and add two environment variables:

  • GAME_BACKEND_URL = the tunnel URL printed above
  • GAME_BACKEND_API_TOKEN = the same value you set in the backend's .env

Step 8: Run the Client​

Point the client at your backend and press play:

GHOSTCHASE_BACKEND_URL=http://127.0.0.1:8080 cargo run -p ghostchase-client

A 1v1 needs two clients. To run both on one machine, give each its own config directory so they get distinct guest identities:

XDG_CONFIG_HOME=/tmp/gc1 GHOSTCHASE_BACKEND_URL=http://127.0.0.1:8080 cargo run -p ghostchase-client
XDG_CONFIG_HOME=/tmp/gc2 GHOSTCHASE_BACKEND_URL=http://127.0.0.1:8080 cargo run -p ghostchase-client

Press play in each: the client enqueues a ticket, GameFlow matches the two players and allocates a server for the match, and both clients connect to it.

Ghost Chase 1v1 in-game

Full Example​

https://github.com/GameFlowGG/gameflow-bevy-multiplayer-example