What is the "Post-Only" order type on Bybit and when should I use it?

Understanding Post-Only Orders

1. A Post-Only order is an instruction that ensures your limit order is added to the order book and never executes immediately against existing orders.

2. If placing the order would result in a match with an opposing order already on the book, Bybit rejects the order instead of executing it as a market taker.

3. This behavior guarantees the trader receives the maker fee rebate rather than paying the higher taker fee.

4. The order remains passive until price movement brings the market to its specified level, at which point it may begin filling incrementally.

5. Post-Only orders are commonly used by liquidity providers who prioritize consistent fee advantages over immediate execution.

How Post-Only Differs From Regular Limit Orders

1. A standard limit order can act as either a maker or taker depending on market conditions at submission time.

2. A Post-Only order enforces strict maker-only status — no exceptions, even if partial fills would otherwise be possible.

3. Bybit’s matching engine validates the order before placement: if the limit price crosses the best available bid or ask, the system declines it outright.

4. Traders receive an explicit error message such as “Order would trade immediately” when attempting invalid Post-Only submissions.

5. This validation step introduces slight latency but eliminates ambiguity about fee classification.

Risks and Limitations

1. Post-Only orders carry slippage risk during fast-moving markets where price gaps past the limit level without triggering any fill.

2. In low-liquidity pairs, the order may sit unfilled for extended durations while volatility erodes the original edge.

3. It cannot be combined with stop triggers or conditional logic — only pure limit-based entry or exit points qualify.

4. Some trading strategies relying on rapid repositioning become impractical due to repeated rejection cycles during volatile sessions.

5. Manual intervention is often required to adjust price levels after rejection, increasing operational overhead.

When to Deploy Post-Only Orders

1. During periods of stable order book depth, especially near key support or resistance zones where price oscillation is expected.

2. When building accumulation or distribution positions across multiple sessions and prioritizing long-term cost efficiency over speed.

3. In arbitrage setups involving correlated assets where precise timing matters less than net funding rate optimization.

4. For algo traders integrating fee-aware execution logic into custom scripts using Bybit’s REST or WebSocket APIs.

5. When participating in liquidity mining programs that explicitly reward sustained order book presence with additional token incentives.

Frequently Asked Questions

Q: Can I cancel a Post-Only order after placement?A: Yes. Once accepted and resting on the order book, it behaves identically to any other limit order and supports full cancellation functionality.

Q: Does Post-Only work with reduce-only positions?A: Yes. Reduce-only logic operates independently of Post-Only enforcement; both flags can be active simultaneously in a single order request.

Q: Are Post-Only orders supported on all Bybit contract types?A: They are available on USDT-margined perpetuals, inverse perpetuals, and futures contracts — but not on spot trading pairs.

Q: What happens if my Post-Only order sits at the top of the book and gets swept?A: It executes fully or partially like any other resting limit order when incoming market orders reach its price level — no special handling applies upon fill.