FIX Authentication

SenderCompID assignment, Logon message structure, password encoding, and session-level authentication for the Kraken Unified FIX API

SenderCompID

Every FIX message — including the initial Logon — requires a SenderCompID (tag 49). This identifier is assigned to you by Kraken during onboarding.

• Spot sessions use your standard SenderCompID
• Derivatives sessions use a SenderCompID with a DRV suffix
• Trading and Market Data sessions use the same SenderCompID but connect to different ports

Contact your Account Manager to request your SenderCompID and connection details.

API Key Setup

Private trading sessions require an API Key with FIX permissions. Create one in Kraken Pro settings.

Session	API Key type needed
Spot trading	FIX key created under your Spot account
Derivatives trading	FIX key created under your Derivatives account

We recommend using separate API Keys for Spot and Derivatives, even though the authentication mechanism is identical.

Authentication Flow

Market Data sessions authenticate with the SenderCompID alone. Trading sessions require an additional HMAC signature:

1. Generate a Nonce — current time in milliseconds since Unix epoch
2. Build the MessageInput string from fixed FIX fields
3. Compute SHA256(MessageInput + Nonce)
4. Sign it with HMAC-SHA512 using your base64-decoded API Secret
5. base64-encode the result → this is your Password (tag 554)
6. Send the Logon with UserName (tag 553), Password (tag 554), and Nonce (tag 5025)

See the Logon page for the full field reference and code examples in Python, Node.js, Java, Go, and C#.