Post-only is an order instruction available on most major crypto exchanges that guarantees your limit order will be placed as a maker — it will only execute if it rests on the order book first. If market conditions shift while your order is being submitted and your limit price would immediately match an existing order, the post-only instruction cancels the order rather than filling it as a taker. This protects you from unexpected taker fees.
For algorithmic traders, bots running grid strategies, and anyone executing high-frequency limit order strategies, enabling post-only on every limit order is considered best practice. The setting is available in the advanced order options on Binance, as a flag in the Binance API, and natively on Kraken, Coinbase Advanced Trade, and most professional trading interfaces. The small risk of order cancellation is far preferable to paying 2x to 6x the fee rate as an accidental taker.
HOW IT WORKS
MECHANISMOrder Rests or Is Cancelled
When you submit a limit order with post-only enabled, the exchange checks if it would immediately match. If yes, the order is cancelled instead of filled. If no match exists, the order rests on the book as a maker.
FEE PROTECTION
BENEFITNever Pay Taker Fee by Accident
Without post-only, a limit order placed near the current market price might fill immediately if the price moves slightly during submission. Post-only prevents this, ensuring you always pay the lower maker fee.
BOT TRADING
ALGO USEEssential for Grid and Bot Strategies
Grid bots and market-making algorithms rely on consistently qualifying for maker fees to remain profitable. Post-only mode is a mandatory setting for these strategies — enabling it can mean the difference between profit and loss.
AVAILABILITY
EXCHANGESAvailable on All Major Platforms
Post-only is supported on Binance (UI and API), Kraken, Coinbase Advanced Trade, Bybit, and most professional trading platforms. It is typically found in the advanced order settings or as an API parameter named 'postOnly' or 'time_in_force: GTX'.
