> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cdp.coinbase.com/llms.txt
> Use this file to discover all available pages before exploring further.

# INTX WebSocket Authentication

You must authenticate when subscribing to the WebSocket Feed the very first time.

To authenticate, include the authentication fields listed below on the subscribe message.

```json lines wrap theme={null}
{
  "type": "SUBSCRIBE",
  "product_ids": ["BTC-PERP"],
  "channels": ["LEVEL2"],
  "time": "1683730727",
  "key": "glK4uG8QRmh3aqnJ",
  "passphrase": "passphrase",
  "signature": "1BM6nwNBLHAkLLs81qcKEKAAPoYIzxTuDIX9DpE0/EM="
}
```

## Authentication Fields

| Field        | Description                                                                                                                                                                    |
| :----------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `key`        | API key used to create the signature                                                                                                                                           |
| `time`       | Timestamp, in epoch seconds, when the request is made. Must be within 30 seconds of making the request.                                                                        |
| `passphrase` | Passphrase affiliated with the API Key                                                                                                                                         |
| `signature`  | HMAC SHA-256 signature with the API Key secret on the concatenated string `TIMESTAMP + KEY + “CBINTLMD” + PASSPHRASE`. Example: `1744594506glK4uG8QRmh3aqnJCBINTLMDpassphrase` |