What you need to know about crypto post only orders in 2026
A post only order is a limit order that will only be placed if it can rest on the order book as a maker order. If the order would match an existing order immediately, the exchange cancels or adjusts it instead of letting it execute. This control matters for crypto traders who want to avoid taker fees, preserve their role as liquidity providers, or run precise automated strategies without unexpected fills.
Post only behavior fits naturally into more advanced trading workflows. High‑frequency strategies, market makers, arbitrage systems, and professional portfolio tools use it to keep tight control over slippage, fees, and execution priority. Even manual traders can use it when they want to participate in liquidity provision without accidentally crossing the spread.
This guide explains how post only orders work in practice, when they are useful, and how they compare to other order types. It is intended for traders who already understand limit and market orders and want more control over how their orders interact with the market.
Understanding how a post only order works
A post only order starts as a standard limit order: you specify a price and size to buy or sell. The difference is in how the exchange or protocol handles it at the moment of submission.
When you send a post only order, the trading system checks whether your limit price would immediately match an existing order. If it would, then instead of executing right away as a taker trade, the system either rejects the order or modifies it so that it sits on the book without crossing the spread. The exact behavior depends on the venue.
On centralized exchanges this usually happens within the matching engine off‑chain. Your order is validated and either posted to the order book as new liquidity or rejected. You see the result almost instantly.
On decentralized exchanges, behavior depends on the design. Order book DEXs that run on a sidechain or rollup may simulate the trade before sending it on-chain, then only submit the transaction if the order will rest as maker liquidity. Aggregators such as CoW Swap route orders across liquidity sources and may support post only semantics when integrating with limit order protocols or RFQ systems. The goal is always the same: never let the order execute immediately against existing liquidity.
This makes post only orders different from normal limit orders, which can act as either maker or taker. It also distinguishes them from "fill or kill" or "immediate or cancel" orders, which prioritize execution speed over providing liquidity.
When to use a post only order
Post only orders work best when your priority is to provide liquidity at specific prices rather than to get an instant fill. They are useful in several situations.
Market makers use post only orders to quote both sides of the market without accidentally trading at worse prices than they intend. By ensuring every order they send becomes resting liquidity, they capture maker rebates where available and avoid unpredictable taker fees.
Discretionary traders may use post only orders when they are willing to wait for a fill and want to earn maker status. For example, a trader might place a post only buy order slightly below the current bid to catch a pullback without risking an immediate execution at a higher price.
Algorithmic bots that run grid trading, range trading, or inventory rebalancing strategies often rely on post only flags. This prevents their logic from placing orders that immediately execute and disrupt their internal models. It is also common in arbitrage bots that only want to provide one side of a trade if certain price conditions across venues are met.
Common parameters used with post only orders include limit price, size, and time‑in‑force. Some systems allow post only combined with "good till canceled" for persistent liquidity, or with "day" orders that expire at the end of a session. Advanced setups may also apply custom risk checks before sending each order.
Advantages and trade-offs
The main benefit of post only orders is fee control. On many venues, maker fees are lower than taker fees, and some platforms even pay rebates to makers. By enforcing maker status, you can improve long‑term trading costs, which matters for high‑volume and high‑frequency strategies.
Post only orders also reduce slippage in the sense that you never pay through the spread. You only trade if the market comes to your price. This aligns with strategies that focus on providing liquidity at edges rather than aggressively chasing fills.
There are trade‑offs. Because your order will not execute immediately, there is always the risk of no fill. In fast markets, the price can move away and never come back, or it can gap through your level without matching if the venue rejects the order to preserve post only behavior. This can lead to missed opportunities.
Execution speed is lower compared with market or aggressive limit orders. If your priority is certainty of entry or exit, post only is often the wrong choice. Liquidity can also be thinner at the specific price levels you choose, so you may only get partially filled.
In terms of flexibility, post only orders are more specialized than regular limit orders. You gain control over your maker status, but you lose the optionality of "if it matches immediately, just fill me." Reliability depends heavily on the venue implementation, especially on DEXs that must balance gas costs, simulations, and routing across multiple pools.
How post only orders fit into automated trading
In automated strategies, post only is typically a flag or parameter in the order placement logic. Bots evaluate market data, decide on a price to quote, and then send limit orders marked as post only. The trading engine or API then enforces the rule that no immediate execution occurs.
For market makers, this feature helps maintain orderly quoting behavior. They might continuously adjust bid and ask orders as the mid‑price moves, always using post only so that any update that would cross the spread either gets rejected or adjusted to the appropriate side.
Aggregators and DEXs incorporate post only semantics by simulating transactions off‑chain and checking for immediate matches. On CoW Swap or similar systems, order intent can be matched peer‑to‑peer or against external liquidity. Post only handling ensures that when users want to act as liquidity providers, their orders do not get consumed instantly by other routes.
Time‑in‑force settings control how long these orders stay active. Strategies may use short lifetimes to avoid stale quotes, combined with price triggers that adjust or cancel orders when volatility spikes. Liquidity routing logic decides where to place post only orders, choosing between multiple venues to maximize rebates or fill probabilities without compromising the maker requirement.
Comparing post only orders to other order types
Post only is one piece of a larger toolkit that includes market, limit, stop, and advanced conditional orders. Each type serves a different purpose.
Unlike a standard limit order, which can be either maker or taker, a post only limit guarantees that you never take liquidity. This is the key distinction. Compared with market orders, post only is at the opposite end of the spectrum: you sacrifice execution certainty and speed in exchange for lower cost and more control over price.
Relative to stop orders, which activate based on a trigger price, post only deals with how the order behaves once it is active, not when it becomes active. You can combine stop logic with post only behavior in some systems, but they address different parts of the execution problem.
For traders choosing between order types, the question is whether they care more about getting filled now or about cost and price control. If the goal is immediate entry or exit, a market or aggressive limit order is more appropriate. If the goal is to earn maker status, provide liquidity, or feed a market making strategy, post only is often the correct tool.
Practical tips for using post only orders effectively
To use post only orders well, start by understanding your venue’s exact behavior. Some exchanges reject any order that would match immediately, while others adjust the price to stay on the book. Test small order sizes to see how your platform behaves before scaling up.
Set limit prices with realistic expectations. If you place orders far away from the current market, you may never get filled. On the other hand, if you quote too aggressively, you increase the chance that the order will be rejected or constantly updated by your bot, which can create unnecessary churn.
Integrate risk management. Do not rely solely on post only flags to protect you from adverse moves. Use position limits, maximum order sizes, and cancel logic when volatility spikes. For automated strategies, log every rejection or cancel, and monitor how often post only behavior prevents execution so you can tune your models.
Beginners should start by adding post only to simple limit orders around clear support and resistance levels and watch how often they get filled. More advanced users can incorporate it into grid strategies, cross‑venue arbitrage, and market making frameworks that adapt continuously to order book depth and spreads.
Conclusion
A post only order is a limit order that enforces maker status by refusing to execute immediately against existing liquidity. It matters because it gives traders control over fees, slippage, and how their orders shape the market, which is especially valuable in high‑frequency and automated environments.
Understanding where post only fits within the broader set of order types helps you choose the right tool for each trading objective. Better control over execution mechanics generally leads to more consistent results and lower hidden costs.
Once you are comfortable with post only behavior, it is worth studying related features such as time‑in‑force, stop and conditional orders, and how different venues implement their matching logic. Mastery of these details often separates casual trading from professional‑grade execution.
FAQ
What is a post only order?
A post only order is a limit order that will only be placed if it can rest on the order book as a maker order. If the order would match an existing order immediately, the exchange cancels or adjusts it instead of letting it execute. This ensures the order never takes liquidity and always provides liquidity to the market.
When should I use post only orders instead of regular limit orders?
Use post only orders when your priority is to provide liquidity at specific prices rather than get an instant fill. They're ideal for market makers who want to quote both sides of the market, discretionary traders willing to wait for fills to earn maker status, and algorithmic strategies like grid trading or arbitrage bots that need to maintain precise control over execution.
What are the main advantages and disadvantages of post only orders?
The main advantages are fee control (lower maker fees or rebates), reduced slippage since you never pay through the spread, and guaranteed maker status. The trade-offs include risk of no fill if the market moves away, slower execution speed compared to market orders, potential partial fills due to thinner liquidity, and less flexibility than regular limit orders.
How do post only orders work differently on centralized versus decentralized exchanges?
On centralized exchanges, post only behavior happens within the matching engine off-chain with near-instant results. On decentralized exchanges, the behavior depends on the design - order book DEXs may simulate trades before sending on-chain transactions, while aggregators route orders across liquidity sources and check for immediate matches to preserve maker status.
What practical tips should I follow when using post only orders?
Start by understanding your venue's exact behavior with small test orders. Set realistic limit prices - not too far from market (no fills) or too aggressive (constant rejections). Integrate proper risk management with position limits and volatility-based cancel logic. Monitor rejection rates to tune your strategy, and begin with simple limit orders around clear support/resistance levels before advancing to complex automated strategies.
