Using the Sec-WebSocket-Protocol

The Sec-WebSocket-Protocol header plays a crucial role in WebSocket communications by enabling the client and server to agree on a specific subprotocol. Subprotocols define a higher-level protocol that runs over the WebSocket connection, specifying the format and semantics of the exchanged messages. This guide aims to provide a comprehensive understanding of how to use this header with Deepgram’s Listen WebSocket and and Speak WebSocket endpoint to facilitate seamless , secure and structured communication.

When utilizing custom subprotocols in WebSocket communications, several security considerations must be addressed to ensure safe and reliable connections. Failure to do so can expose both the client and server to various risks, including unauthorized access, data breaches, and denial-of-service attacks.

1. Authentication and Authorization:

   • Verify client identities and ensure proper permissions for actions.

2. Data Encryption:

   • Use TLS (wss://) to encrypt connections and consider end-to-end encryption for data payloads.

3. Input Validation and Sanitization:

   • Rigorously validate and sanitize all incoming data to prevent injection attacks.

4. Rate Limiting and Throttling:

   • Implement mechanisms to prevent abuse and denial-of-service (DoS) attacks.

5. Message Integrity:

   • Use integrity checks to ensure messages are untampered during transit.

6. Session Management:

   • Securely manage and expire sessions to prevent hijacking.

7. Error Handling:

   • Handle errors gracefully without exposing internal details.

8. Protection Against Common Attacks:

   • Mitigate risks from attacks like Cross-Site WebSocket Hijacking, XSS, and CSRF.

9. Custom Subprotocol Security:

   • Design secure subprotocols and regularly review their implementation for vulnerabilities.

10. Compliance and Best Practices:

• Ensure compliance with relevant security standards and follow industry best practices for secure WebSocket communication.

To use the Sec-WebSocket-Protocol header with Deepgram’s Listen WebSocket endpoint, follow this example:

GET /listen HTTP/1.1
Host: wss://api.deepgram.com/
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: <calculated at runtime>
Sec-WebSocket-Version: 13
Sec-WebSocket-Protocol: token, YOUR_DEEPGRAM_API_KEY

In this example, the Sec-WebSocket-Protocol header specifies two subprotocols: token and a valid Deepgram API Key. During the WebSocket handshake, the server will select one of these subprotocols for the communication and authentication.

To use the Sec-WebSocket-Protocol header with Deepgram’s Speak WebSocket endpoint, follow this example:

GET /speak HTTP/1.1
Host: wss://api.deepgram.com/
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: <calculated at runtime>
Sec-WebSocket-Version: 13
Sec-WebSocket-Protocol: token, YOUR_DEEPGRAM_API_KEY

In this example, the Sec-WebSocket-Protocol header specifies two subprotocols: token and a valid Deepgram API Key. During the WebSocket handshake, the server will select one of these subprotocols for the communication and authentication.