How to use 'Post-Only' orders on Kraken Pro? (Maker fee optimization)

Understanding Post-Only Order Mechanics

1. A Post-Only order is designed to ensure the order is added to the order book and never executes immediately against an existing counter-order.

2. If placement would result in immediate execution—even partial—the exchange rejects the order outright instead of converting it into a market or hybrid order.

3. Kraken Pro enforces this behavior strictly on both limit buy and limit sell orders across all trading pairs supported on the Pro interface.

4. The system validates the Post-Only condition at the exact moment of submission, checking price alignment with the best available bid or ask before insertion.

5. Rejection messages include precise error codes such as “PostOnlyViolation” to help traders diagnose misconfigured parameters.

Enabling Post-Only on Kraken Pro Interface

1. Navigate to the Kraken Pro trading dashboard and select the desired trading pair.

2. Click the “Advanced” toggle beneath the order entry panel to expose additional order type options.

3. Check the box labeled “Post-Only” before submitting any limit order—this setting persists per session unless manually disabled.

4. Confirm that the order preview displays “Post-Only: Yes” alongside fee estimates reflecting maker-tier pricing.

5. Submit the order only after verifying that the limit price does not cross the opposing side’s top-of-book level.

Fee Implications and Maker Status Preservation

1. Orders executed as makers receive Kraken’s lowest applicable fee tier, which for verified Tier 4 accounts starts at 0.00% for BTC/USD and other major pairs.

2. A Post-Only order guarantees maker status by design, provided it remains unfilled upon submission and enters the order book cleanly.

3. Partial fills do not compromise maker eligibility—each executed portion retains its original maker classification for fee calculation purposes.

4. Cancellation of a Post-Only order incurs no fee, reinforcing its role as a low-risk strategy for liquidity provision without commitment.

5. Fee rebates are applied automatically when applicable, visible in the transaction history under “Maker Rebate” entries.

Common Misconfigurations and Failures

1. Setting a buy order at or above the current best ask triggers immediate matching and causes rejection with Post-Only enabled.

2. Placing a sell order at or below the current best bid produces identical rejection behavior due to violation of resting-only logic.

3. Using Post-Only during high-volatility events increases rejection frequency as spreads widen and order book depth fluctuates rapidly.

4. API users must explicitly set the post_only=true parameter in the order payload; omission defaults to regular limit behavior.

5. Mobile app versions of Kraken do not support Post-Only toggles—this functionality remains exclusive to Kraken Pro web and desktop clients.

Frequently Asked Questions

Q: Does Kraken charge a fee if a Post-Only order gets rejected?A: No. Kraken does not assess any fee for rejected Post-Only orders regardless of reason or frequency.

Q: Can I combine Post-Only with Stop-Limit or Take-Profit orders?A: No. Kraken Pro does not permit Post-Only activation on conditional order types. Only standard limit orders support this flag.

Q: Is there a time-in-force restriction for Post-Only orders?A: Post-Only orders default to GTC (Good-Til-Cancelled), but users may manually select IOC or GTD modes—though IOC will almost always fail under Post-Only rules.

Q: Do Post-Only orders appear in the public order book before full validation?A: No. Kraken performs atomic validation prior to any book insertion. Visibility occurs only after successful placement.