jcentserver-client demos

Runnable examples for jcentserver-client and Centrifugo 6.

Demo	What it demonstrates	Server port	Client port
chat	Multi-room chat with cached history	8080	5173
datachannel	WebRTC data-channel signaling	8080	5173
gauge	Live gauge telemetry	8080	5173
iss	ISS tracking with a server-side subscription	8080	5173
map-cursors	Ephemeral map-subscription cursors and server-side clear	8094	4177
maps	Live vehicle positions on a map	8080	5173
pg-orders	Transactional PostgreSQL stream broker and state recovery	8096	4179
poll	Persistent live poll	8080	5173
presence-dashboard	Presence, presence stats, and join/leave events	8093	4176
recovery-lab	Reconnect and publication recovery	8092	4175
shared-poll-votes	HMAC-authorized shared-poll tracking and publishing	8095	4178
simple-chat	Minimal real-time chat	8080	5173
simple-chat-2	Chat with participant counts and typing indicators	8080	5173
smoothie	Scrolling CPU telemetry charts	8080	5173
snake	Multiplayer snake game	8080	5173
tennis-delta	Plain versus Fossil delta-compressed match feeds	8091	4174
whiteboard	Collaborative pointer, touch, and pen drawing	8080	5173

Requirements

• Java 25
• Node.js 20.19+ or 22.12+
• Docker Compose
• A MapTiler API key for iss and maps

Run a demo

Start the shared Centrifugo and PostgreSQL services from the repository root:

docker compose up -d

Then start one server and its matching client in separate terminals. For example:

cd chat/server
./mvnw spring-boot:run

cd chat/client
npm install
npm run dev

On Windows, use mvnw.cmd instead of ./mvnw. The older demos share ports 8080 and 5173, so run only one of those pairs at a time. The six Centrifugo 6.8 feature demos use the dedicated ports in the table and can run together.

For iss and maps, create a client .env.local file containing:

VITE_MAPTILER_API_KEY=your-key

Every client also supports optional endpoint overrides:

VITE_SERVER_URL=http://localhost:8080
VITE_CENTRIFUGO_BASE_ADDRESS=localhost:8000

pg-orders requires the PostgreSQL service from the root Compose stack. Centrifugo creates its cf_stream_* functions and controller schema when it starts.