Explore Hub: Risk Management and Execution
post-only order reject reasons matter most when a good crypto setup suddenly becomes fast. Traders often select post-only to avoid taker fees and keep entry discipline, then panic when the exchange rejects the order just as the signal starts moving. The answer is not to spam the button again. The answer is to understand why the order was rejected and what that says about the trade environment.
CryptoSigy treats post-only as an execution control. It protects queue position and fee profile only if the trader also understands the rejection states around it. A rejected post-only order is useful information: it tells you the book, the spread, or your own price logic is no longer aligned with a passive entry.
What post-only is trying to do
A post-only order is supposed to rest on the book without immediately crossing the spread. If the order would execute as a taker, the exchange cancels or rejects it. That makes post-only ideal for traders who want maker fees, passive fills, or a tighter handle on entry drift.
The hidden trap is that many traders treat post-only as a guaranteed entry method. It is not. It is a conditional order style. The moment the market starts moving too quickly, the exchange is telling you that your price is no longer passive.
Reject reason one: your price crossed the spread
This is the classic case. A long entry priced at or above the best ask can no longer remain passive, so the exchange rejects it. The same problem happens on shorts when the order is priced at or below the best bid. In fast markets this can happen even when the trader clicked a passive price because the spread moved during the short gap between quote view and order placement.
That gap matters more when signals are taken from another screen, copied manually, or sent during a news burst. The rejection is not bad luck. It is evidence that the market moved faster than your passive workflow.
Reject reason two: tick size and price precision
Some rejects look like spread problems but actually come from price formatting. If the instrument uses a wider tick size than expected, a carefully chosen passive number may round up into a crossing price. The same issue appears when traders reuse a template across pairs with different precision rules.
Before a fast entry, check the pair's minimum price increment and minimum notional. Small formatting errors become expensive when the fallback response is to chase the market with a worse order type.
Reject reason three: the market state changed under you
Listings, reopenings after maintenance, high-volatility sessions, and thin overnight books can create market states where the best displayed quote is not stable enough for passive execution. A post-only reject in those conditions is a reminder that the displayed spread may not be trustworthy for more than a moment.
That is why advanced traders separate “idea quality” from “entry quality.” The trade thesis may still be fine. The specific passive entry may no longer be available. Good execution means recognizing that difference quickly.
Reject reason four: exchange protections are blocking the passive plan
Some venues layer post-only behavior with price bands, auction states, self-trade prevention, or special launch-mode controls. A trader who only sees “rejected” may assume the order was wrong, when the real issue is that the exchange is protecting the market from unstable prints or disallowed behavior.
These are not edge cases during event-driven trading. They show up exactly when many traders are most tempted to override their rules. The correct response is to know the venue controls before the signal hits.
Have a reject plan before the entry
The best defense is pre-commitment. Decide whether a reject means reprice once, convert to a different limit level, or skip the trade entirely. If you do not define that rule before the market speeds up, the default human behavior is usually to chase.
A clean journal note helps too. Record whether the reject came from spread crossing, tick size, market state, or venue controls. Over time you will see which pairs and which exchanges are worth a passive entry workflow and which ones keep forcing you into worse execution.
Use rejections as execution data
Post-only rejects are frustrating only when they are treated as interruptions. Used correctly, they are execution feedback. They tell you the spread is unstable, the pair rules were misread, or the venue is in a state where passive entry is unrealistic. That is exactly the information a signal trader needs.
The goal is not to force every good setup into a maker fill. The goal is to know when a passive entry still exists and when the trade has moved out of your preferred execution zone.
