What Is a Post-Only Order in Crypto?

What Is a Post-Only Order in Crypto?

⏱ 6 min read

You’re staring at the order book, finger hovering over the buy button. You want to grab that dip on Bitcoin, but you know the fee structure — if you jump the queue and take liquidity, you’ll get hit with a taker fee. That’s where the post-only order comes in. It’s one of those under-the-radar features that can quietly save you a ton of money over time. Sound familiar? Let’s break it down.

What Exactly Is a Post-Only Order?

A post-only order is a type of limit order that guarantees your trade adds liquidity to the order book instead of removing it. In simple terms: you’re placing an order that sits there waiting to be matched — you’re the “maker,” not the “taker.”

Here’s the key rule: if your post-only order would immediately match against an existing order on the book (meaning it would be a taker trade), the exchange cancels the order instead of executing it. No fill, no fee. You get a notification saying the order was rejected because it wasn’t post-only compliant.

Think of it like standing in line at a busy coffee shop. A post-only order means you join the back of the line and wait your turn. A taker order is you cutting to the front and grabbing the next available cup. The barista (exchange) charges you extra for cutting.

This feature is baked into most major crypto exchanges now — including Binance, Bybit, Kraken, and OKX. It’s especially common on perpetual futures markets where fee structures are tiered.

How Does a Post-Only Order Work in Crypto?

When you place a post-only order, the exchange runs a quick check before adding it to the order book. The logic is simple:

• If your limit price is better than the best existing price — say you’re buying Bitcoin at $60,100 but the best ask is $60,000 — your order would immediately match against that $60,000 sell order. That makes you a taker. The exchange cancels your post-only order.
• If your limit price is at or behind the current spread — say you’re buying at $59,900 and the best ask is $60,000 — your order sits in the book. You’re a maker. The order stays live.

Most exchanges let you toggle this option when placing a limit order. On Binance Futures, for example, you’ll see a checkbox labeled “Post Only” right next to the limit price field. On Bybit, it’s in the order type dropdown.

One thing to watch out for: some exchanges treat post-only orders differently during high volatility. If the market moves fast and your price suddenly becomes marketable, the order gets killed — not filled. That can be frustrating if you really wanted the position. But that’s the trade-off for lower fees.

Here’s a real-world scenario: I was trying to short Ethereum at $3,200 last month. I set a post-only sell limit at $3,205, hoping to catch a small bounce. The order sat for about 20 minutes, then got canceled when ETH jumped to $3,210. I had to re-enter at a worse price. Annoying? Yeah. But I saved 0.04% on fees each time I got a fill, and over a month that adds up to real money.

Why Should Traders Use Post-Only Orders?

The biggest reason is fee savings. Most exchanges charge a maker fee of 0.01-0.02% and a taker fee of 0.04-0.06%. For high-volume traders, that difference is massive. If you’re executing $100,000 in trades daily, switching from taker to maker saves you $30-50 per day — $1,000+ per month.

But it’s not just about fees. Post-only orders help you avoid slippage on large positions. When you place a regular market order, you eat through the order book, getting progressively worse fills. A post-only order lets you pick your spot and wait. You control the price.

Another advantage: order book analysis. When you see a cluster of post-only orders at a specific level, you know someone with deep pockets is trying to add liquidity there. That’s a signal — especially on perpetual futures. For more on reading order book signals, check out AI Reversal Strategy with Confluence Zone Entry.

There’s also a psychological benefit. Using post-only orders forces you to be patient. You can’t just smash the buy button. You have to think about where you want to enter, set your limit, and wait. That discipline alone can improve your trading.

But let’s be real — post-only isn’t for every trade. If you need to get in or out fast (say, during a flash crash), you don’t want a post-only order. It’ll just get canceled. Use it when you have time and want to save money. Use market orders when speed matters.

Can You Use Post-Only Orders on Any Exchange?

Most major exchanges support post-only orders, but the implementation varies. Here’s a quick breakdown:

• Binance — Available on spot and futures. Checkbox in the order form. Works with limit orders only.
• Bybit — Available on perpetuals. Can be combined with reduce-only or IOC orders.
• Kraken — Available on spot and futures. Called “post-only” in the advanced order menu.
• OKX — Available on spot and futures. Toggle in the order type selector.
• Coinbase — Not available on the standard interface. You’d need to use the API or Pro tools.

One thing to note: some exchanges have minimum order sizes for post-only orders. On Binance Futures, for example, your order must be at least $10 notional value. Small traders should check this before relying on the feature.

Also, post-only orders interact with other order flags. You can combine post-only with “reduce-only” on futures exchanges — that’s useful for closing positions without taking fees. But you can’t combine post-only with “IOC” (immediate-or-cancel) or “FOK” (fill-or-kill) because those orders are designed to execute immediately.

If you’re trading on a decentralized exchange (DEX), post-only orders are rare. Most DEXs use AMM models where you’re always trading against a pool — there’s no order book to add liquidity to. For more on DEX trading mechanics, see AI Momentum Strategy for MNT.

FAQ

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FAQ

Q: Can a post-only order get partially filled?

A: Yes, a post-only order can get partially filled if only part of your order matches against incoming market orders. The unfilled portion stays on the order book as maker liquidity. You’ll pay maker fees on the filled portion only.

Q: What happens to a post-only order during high volatility?

A: During high volatility, if the market price moves past your limit price, your post-only order will be canceled instead of filled. This is because the order becomes immediately executable, which violates the post-only rule. You’ll need to re-place the order at a new price.

So Where Do You Go From Here?

You’ve got the tool — now go test it on a small position. Set a post-only order on your next trade, watch how it behaves, and track the fee difference. Most traders never touch this setting, and they’re leaving money on the table. Are you going to be one of them?