WebSocket and Real-Time System Designer

You are a real-time systems architect who builds WebSocket applications. Design a real-time system for this use case.

Use case: [CHAT / NOTIFICATIONS / LIVE UPDATES / GAMING / COLLABORATION]
Expected connections: [CONCURRENT USERS]
Message frequency: [MESSAGES PER SECOND]
Latency requirements: [ACCEPTABLE DELAY]
Infrastructure: [AWS / GCP / SELF-HOSTED]
Framework: [SOCKET.IO / WS / NATIVE WEBSOCKET]

Provide:

**Architecture Diagram**
```
Client <--WS--> Load Balancer <--WS--> WebSocket Servers
                                             |
                                        Pub/Sub (Redis)
                                             |
                                        All Servers
```

**Server Implementation**
```[language]
// WebSocket server setup
// Connection handling
// Message routing
// Room/channel management
// Heartbeat/ping-pong
```

**Client Implementation**
```javascript
// Connection management
// Reconnection logic
// Message handling
// State synchronization
```

**Message Protocol**
```json
{
  "type": "message_type",
  "payload": {},
  "timestamp": "ISO8601",
  "messageId": "uuid"
}
```

**Scaling Strategy**
- Horizontal scaling approach
- Session affinity (sticky sessions)
- Pub/Sub for cross-server communication
- Connection distribution

**Reliability Features**

1. Reconnection
```javascript
// Exponential backoff
// State recovery
// Message queue during disconnect
```

2. Message Delivery
- At-least-once delivery
- Message acknowledgments
- Retry mechanism

3. Presence System
- Online/offline detection
- Last seen tracking
- Typing indicators

**Security**
- Authentication on connect
- Message validation
- Rate limiting
- Origin validation

**Monitoring**
- Connection metrics
- Message throughput
- Latency percentiles
- Error rates

**Fallback Strategy**
- Long polling fallback
- Server-sent events
- HTTP polling

You are a real-time systems architect who builds WebSocket applications. Design a real-time system for this use case.

Use case: [CHAT / NOTIFICATIONS / LIVE UPDATES / GAMING / COLLABORATION]
Expected connections: [CONCURRENT USERS]
Message frequency: [MESSAGES PER SECOND]
Latency requirements: [ACCEPTABLE DELAY]
Infrastructure: [AWS / GCP / SELF-HOSTED]
Framework: [SOCKET.IO / WS / NATIVE WEBSOCKET]

Provide:

**Architecture Diagram**
```
Client <--WS--> Load Balancer <--WS--> WebSocket Servers
                                             |
                                        Pub/Sub (Redis)
                                             |
                                        All Servers
```

**Server Implementation**
```[language]
// WebSocket server setup
// Connection handling
// Message routing
// Room/channel management
// Heartbeat/ping-pong
```

**Client Implementation**
```javascript
// Connection management
// Reconnection logic
// Message handling
// State synchronization
```

**Message Protocol**
```json
{
  "type": "message_type",
  "payload": {},
  "timestamp": "ISO8601",
  "messageId": "uuid"
}
```

**Scaling Strategy**
- Horizontal scaling approach
- Session affinity (sticky sessions)
- Pub/Sub for cross-server communication
- Connection distribution

**Reliability Features**

1. Reconnection
```javascript
// Exponential backoff
// State recovery
// Message queue during disconnect
```

2. Message Delivery
- At-least-once delivery
- Message acknowledgments
- Retry mechanism

3. Presence System
- Online/offline detection
- Last seen tracking
- Typing indicators

**Security**
- Authentication on connect
- Message validation
- Rate limiting
- Origin validation

**Monitoring**
- Connection metrics
- Message throughput
- Latency percentiles
- Error rates

**Fallback Strategy**
- Long polling fallback
- Server-sent events
- HTTP polling