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.

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

​
Authentication Fields

FieldDescription
keyAPI key used to create the signature
timeTimestamp, in epoch seconds, when the request is made. Must be within 30 seconds of making the request.
passphrasePassphrase affiliated with the API Key
signatureHMAC SHA-256 signature with the API Key secret on the concatenated string TIMESTAMP + KEY + “CBINTLMD” + PASSPHRASE. Example: 1744594506glK4uG8QRmh3aqnJCBINTLMDpassphrase