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Connect to the Sports WebSocket to receive real-time sports results. No authentication required—just connect and handle incoming messages.

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Endpoint

wss://sports-api.polymarket.com/ws

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JavaScript Example

const ws = new WebSocket('wss://sports-api.polymarket.com/ws');

ws.onopen = () => {
  console.log('Connected to Sports WebSocket');
};

ws.onmessage = (event) => {
  // Respond to server PING
  if (event.data === 'ping') {
    ws.send('pong');
    return;
  }

  // Parse and handle sports updates
  const data = JSON.parse(event.data);
  console.log('Update:', data.slug, data.score, data.period);
};

ws.onclose = () => {
  console.log('Disconnected');
  // Reconnect after 1 second
  setTimeout(() => location.reload(), 1000);
};

ws.onerror = (error) => {
  console.error('WebSocket error:', error);
};

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Critical: PING/PONG Handling

The server sends PING messages every 5 seconds. Your client must respond with PONG to stay connected. 
// CORRECT - Handle PING messages
ws.onmessage = (event) => {
  if (event.data === 'ping') {
    ws.send('pong');  // Respond immediately
    return;
  }
  // Handle other messages...
  const data = JSON.parse(event.data);
  handleUpdate(data);
};

// WRONG - Ignoring PING messages will disconnect you
ws.onmessage = (event) => {
  const data = JSON.parse(event.data);  // Fails on "ping" string!
  handleUpdate(data);
};
If you don’t respond to PING within 10 seconds, your connection will be terminated.

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Connection State Management

Always check connection state before sending: 
if (ws.readyState === WebSocket.OPEN) {
  ws.send('pong');
} else {
  console.warn('WebSocket not connected');
}

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Browser Tab Visibility

Connections may drop when browser tabs become inactive. Handle visibility changes: 
document.addEventListener('visibilitychange', () => {
  if (!document.hidden && ws.readyState !== WebSocket.OPEN) {
    console.log('Tab became visible, reconnecting...');
    connect();
  }
});

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Troubleshooting

Your PING/PONG handler isn’t working correctly.Check:
  • You’re responding to "ping" string messages (not JSON)
  • You’re sending "pong" as a string response
  • No errors are preventing the PONG from being sent
// Debug PING/PONG handling
ws.onmessage = (event) => {
  console.log('Received:', event.data);
  if (event.data === 'ping') {
    console.log('Sending PONG response');
    ws.send('pong');
    return;
  }
  // Handle JSON messages...
};
This may be network instability or main thread blocking.Solutions:
  • Implement exponential backoff for reconnection
  • Ensure your message handler doesn’t block the main thread
  • Check network stability
handleReconnect() {
  this.reconnectDelay = Math.min(this.reconnectDelay * 2, 30000);
  setTimeout(() => this.connect(), this.reconnectDelay);
}
Ensure you’re updating state correctly based on the slug identifier.
// Use slug as unique key
setSportsData(prev => {
  const index = prev.findIndex(item => item.slug === data.slug);
  if (index >= 0) {
    const updated = [...prev];
    updated[index] = data;
    return updated;
  }
  return [...prev, data];
});
Clean up properly when disconnecting:
const cleanup = () => {
  if (reconnectTimeout) {
    clearTimeout(reconnectTimeout);
  }
  if (ws) {
    ws.close();
    ws = null;
  }
};

// React: cleanup in useEffect return
// Vanilla: call on page unload
window.addEventListener('beforeunload', cleanup);

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Debugging Tips

Enable verbose logging to diagnose connection issues: 
ws.onopen = () => console.log('[connected]');
ws.onclose = (e) => console.log('[closed]', e.code, e.reason);
ws.onerror = (e) => console.error('[error]', e);
ws.onmessage = (e) => console.log('[message]', e.data);
Monitor connection state: 
setInterval(() => {
  const states = ['CONNECTING', 'OPEN', 'CLOSING', 'CLOSED'];
  console.log('WebSocket state:', states[ws.readyState]);
}, 5000);