Why Did My Limit Order Pay Taker Fees? Post-Only Explained
CryptoRebateHub Editorial Team
A limit order controls the worst price, not the liquidity role. Learn marketable limits, post-only behavior, partial fills, and audit fields.
A limit order protects the worst acceptable price; it does not guarantee maker status. If it can execute immediately against the book, it removes liquidity and pays taker fees.
Marketable limit order example
With best bid 99.90 and best ask 100.00, a buy limit at 100.10 can immediately trade at 100.00 and is taker. A buy limit at 99.90 rests and is normally maker. A sell limit at 99.80 crosses the bid; a sell at 100.10 rests.
What post-only changes
Post Only, maker-only, or a venue-specific equivalent requires the order to rest before trading. If it would execute immediately, the venue may reject, cancel, or reprice it under a documented rule. The benefit is fee-role control; the cost is non-fill risk.
Why one order can show mixed fees
Part of an order may trade immediately while the remainder rests. A modification can cross the book. The market can move between local observation and exchange receipt. A triggered stop-limit can create a marketable limit. Audit individual fills, not only the order status.
Fields to preserve
Store local send time, exchange acknowledgement, time-in-force, limit price, best bid and ask at submission, maker/taker flag per fill, fee amount, and post-only setting. A bot should use exchange receipts rather than infer liquidity role from candles.
When not to force maker
Protective stops, emergency risk reduction, and rapidly disappearing liquidity may justify taker execution. Missing a stop to save a few bps can cost much more. Maker/taker is an execution trade-off, not a universal ranking. Use the fee comparison tool to quantify the difference.
FAQ
Is a market order always taker?
It normally removes available liquidity, so it is generally taker.
Does post-only guarantee a fill?
No. It only prevents intentional liquidity taking.
How are partial fills charged?
Each fill can have its own maker/taker flag and fee.
Bottom line
Limit is not synonymous with maker. Use post-only when non-fill risk is acceptable, but do not let fee optimization override protective execution.
