Futures Websockets
Sign challenge
The subscribe and unsubscribe requests to WebSocket private feeds require a signed challenge message with the user api_secret.
The challenge is obtained as is shown in Section WebSocket API Public (using the api_key).
Authenticated requests must include both the original challenge message (original_challenge) and the signed (signed_challenge) in JSON format.
Challenge
Challenge example
c100b894-1729-464d-ace1-52dbce11db42
The challenge is a UUID string.
The steps to sign the challenge are the same as the steps to generate an authenticated HTTP request except for step 1 which now is just the challenge string:
- Hash the challenge with the SHA-256 algorithm
- Base64-decode your
api_secret - Use the result of step 2 to hash the result of step 1 with the HMAC-SHA-512 algorithm
- Base64-encode the result of step 3
The result of the step 4 is the signed challenge which will be included in the subscribe request.
The table below shows the expected output from example inputs:
| Name | Value |
|---|---|
challenge | c100b894-1729-464d-ace1-52dbce11db42 |
api_secret | 7zxMEF5p/Z8l2p2U7Ghv6x14Af+Fx+92tPgUdVQ748FOIrEoT9bgT+bTRfXc5pz8na+hL/QdrCVG7bh9KpT0eMTm |
| signed output | 4JEpF3ix66GA2B+ooK128Ift4XQVtc137N9yeg4Kqsn9PI0Kpzbysl9M1IeCEdjg0zl00wkVqcsnG4bmnlMb3A== |
Subscriptions
Subscriptions requests are sent through a web socket connection.
To subscribe to a feed, a web socket connection is required to establish a connection using the following URL:
wss://futures.kraken.com/ws/v1
Keeping the connection alive
In order to keep the websocket connection alive, you will need to make a ping request at least every 60 seconds. You can see this in our sample implementation.
Snapshots and updates
For ease of use, most web socket feeds first send a snapshot of the history or current state and subsequently send real-time updates.
Authentication
In order to subscription to a private feed, clients must pass a challenge which involves signing a message (see Section Sign Challenge) with the private API key. First, a message must be sent to request the challenge. Second, the solved challenge has to be passed in every subscribe and unsubscribe message that is sent.