WebSocket Security and Reliability
WebSocket connections persist for long periods, which creates security and reliability challenges different from traditional HTTP requests. A dropped connection at the wrong moment can lose important data. An unauthenticated connection can expose sensitive information. Building production-ready real-time systems means addressing both concerns.
Authentication Strategies
Unlike HTTP requests where you can include authentication headers easily, WebSocket authentication requires different approaches.
Token in connection URL is simple but problematic — tokens appear in server logs and browser history:
// Avoid if possible - token visible in logs
new WebSocket('wss://example.com/chat?token=xxx');
Send token after connecting keeps credentials out of URLs:
ws.onopen = () => {
ws.send(JSON.stringify({ type: 'auth', token: 'xxx' }));
};
// Server validates token before accepting other messages
Cookie-based authentication works automatically for same-origin connections. The browser sends cookies with the WebSocket handshake, just like HTTP requests. This approach integrates well with existing session management.
Handling Disconnections
Connections will drop — networks fail, servers restart, users switch between Wi-Fi and cellular. Your application must handle this gracefully.
Implement reconnection with exponential backoff to avoid overwhelming your server:
let attempts = 0;
function connect() {
const ws = new WebSocket('wss://example.com/chat');
ws.onopen = () => {
attempts = 0; // Reset on successful connection
};
ws.onclose = () => {
const delay = Math.min(1000 * Math.pow(2, attempts), 30000);
attempts++;
setTimeout(connect, delay);
};
}
This pattern starts with a 1-second delay, doubles each attempt, and caps at 30 seconds. Users get quick reconnection for brief hiccups while avoiding connection storms during outages.
Security Considerations
Always use WSS (WebSocket Secure) in production — it's the WebSocket equivalent of HTTPS. Unencrypted WebSocket traffic can be intercepted and modified.
Validate the Origin header on your server to prevent cross-site WebSocket hijacking. Only accept connections from your own domains.
Rate limit connections to prevent denial-of-service attacks. Limit both connection attempts per IP and messages per connection.
Validate all incoming messages just like you would HTTP request bodies. Never trust client data — parse it carefully and reject malformed messages.
Timeout idle connections to free server resources. If a client hasn't sent a heartbeat or message within your timeout period, close the connection.
Message Integrity
For critical operations, implement acknowledgment patterns. When the server receives an important message, send back a confirmation. If the client doesn't receive acknowledgment within a timeout, retry the message after reconnecting.
This prevents data loss during disconnections — you'll know exactly which messages made it through.