Coup

Starter fullstack project for an online game of Coup using SvelteKit + TypeScript.

Included

• SvelteKit frontend with lobby and game table views
• In-memory server game engine for Coup-like turns and actions
• API endpoints for create/join/start/action flows
• WebSocket-based live updates on the game page

Game Flow

• Create a game from /
• Share the 6-character game ID
• Other players join the table
• Host starts the game
• Players take turns with these actions:
  • income, foreign_aid, tax, steal, assassinate, coup, exchange

Rules implemented:

• Action challenges for claim-based actions (tax, steal, assassinate, exchange)
• Blocking flow (foreign_aid, steal, assassinate) with block challenges
• Manual influence reveal choices when a player loses influence
• Ambassador exchange flow (draw 2, choose cards to keep, return/shuffle remainder)
• Automatic host transfer when the host disconnects
• Manual host transfer and host kick controls from the game table UI
• Player connection + device indicators in the player list

API Endpoints

• POST /api/games create game { name }
• GET /api/games/:gameId?playerId=... get public game state
• POST /api/games/:gameId/join join game { name }
• POST /api/games/:gameId/start host starts game { playerId }
• POST /api/games/:gameId/action submit command { playerId, command }
• POST /api/games/:gameId/host transfer host { playerId, targetId }
• POST /api/games/:gameId/kick kick a player { playerId, targetId }

Run

bun install
bun run dev

Optional realtime config:

# websocket server + client port for local development (defaults to 24678)
COUP_WS_PORT=24678 VITE_COUP_WS_PORT=24678 bun run dev

# or point the client at a full websocket URL
VITE_COUP_WS_URL=wss://coup.example.com:24678 bun run build

Type checks:

bun run check

Run With Docker

docker compose up --build

The container serves the SvelteKit app on port 3000 and the realtime WebSocket server on port 24678.

Caddy should proxy HTTP requests to the app and WebSocket upgrades to the realtime server on the same public origin, for example:

coup.example.com {
	@websocket {
		header Connection *Upgrade*
		header Upgrade websocket
	}

	handle @websocket {
		reverse_proxy coup:24678 {
			transport http {
				read_timeout 0
				write_timeout 0
			}
		}
	}

	handle {
		reverse_proxy coup:3000
	}
}