Trading tools, told plainly
Reading a DEX order book screen
An order book screen shows every open buy and sell order for a trading pair: the bids, the asks, the gap between them, and the depth stacked at each price. This guide explains the screen in plain words: bids and asks, the spread, order depth, market orders and limit orders, slippage, and a calm routine for reading it all.
Reviewed and current as of September 12, 2026
01Bids and asks
Picture a farmers market at dawn. Sellers set out their produce with price tags, and buyers walk the rows holding up signs with the price they are willing to pay. An order book shows that same scene on a screen: asks are the sellers listing the price they will accept, and bids are the buyers naming the price they will pay.
Bids sit on one side, asks on the other, and the screen keeps them sorted so the best prices are always on top. Reading them together shows you exactly what the market wants at this moment, in real terms, with real orders behind every number.
02The spread
The spread is the gap between the highest bid and the lowest ask. When the gap is tiny, buyers and sellers are in close agreement and the market feels lively. When the gap is wide, the market feels quiet and prices can jump between trades.
A tight spread is a green light for small, easy trades. A wide spread is an invitation to slow down, use limit orders, and wait for better agreement before you act.
03Order depth
Order depth shows how much coin waits at each price level. A thick stack of orders near the current price means your trade can fill calmly, because plenty of orders are ready to meet it. A thin stack means your trade may move the price as it sweeps through one level after another.
Depth turns the screen from a single price into a full landscape. You see more than the current price: you see how much support stands behind it.
04Market orders and limit orders
A market order fills right away at the best prices available, which suits a fast move. A limit order names your price and waits for the market to come to you, which suits a patient plan. Most order book screens let you choose between them with one tap.
Market orders give you speed and certainty of filling. Limit orders give you price control and add depth for everyone else. Knowing which tool fits the moment is half the skill of reading the screen.
05Slippage
Slippage is the price moving between the moment you tap and the moment your trade fills. It grows when your trade is large compared to the depth waiting for it, since your order reaches into further price levels to finish filling.
Traders set a slippage limit so a trade fills only if the price stays close to what they saw. A small limit keeps surprises small. Reading the depth first shows you whether the limit you set fits the market you are trading in.
06A calm routine
Check the spread first, since a tight spread means a healthy market. Choose limit orders when patience serves you, and market orders when speed matters more. Start small while you learn the screen, and size each trade to the depth you see.
Review your fills after each session, and you will start to see how depth, spread, and slippage dance together. That quiet reading habit keeps your trades calm, your expectations honest, and your curiosity sharp. The next order book you meet holds its price story in the open, and now you know how to read it.
01What is an order book on a DEX?
An order book lists every open buy order and sell order for one trading pair, sorted so the best prices sit on top. Bids are buyer orders, asks are seller orders. It shows what the market wants right now, with real orders behind every price.
02What is the spread on an order book?
The spread is the gap between the highest bid and the lowest ask. A tiny gap means buyers and sellers agree closely and trading feels smooth. A wide gap means the market is quieter and prices can jump between trades.
03What is the difference between a market order and a limit order?
A market order fills right away at the best prices available, giving you speed. A limit order names your price and waits for the market to reach it, giving you price control. Market orders take liquidity, while limit orders add it.
04What is slippage in crypto trading?
Slippage is the price moving between the moment you place a trade and the moment it fills. It grows when your trade is large compared to the orders waiting in the book. Traders set a slippage limit so the trade fills only if the price stays near what they saw.
05How do I read order book depth?
Look at how much coin waits at each price level. Thick stacks near the current price mean smooth fills. Thin stacks mean your trade may push the price through several levels. Checking depth before trading helps you size your trade to the market.