Crypto Infrastructure
You can have speed, or you can have your price. Not both.
An exchange is not a buy button, it is a market mechanism: an order, a book of everyone else's open orders, and an engine that pairs them. The order type you pick decides which half of the deal you give away.
The problem
Speed or price. Pick one.
One buy order for bitcoin, placed twice into the same book — once as a market order, once as a limit order. Run both and watch the two lines at the bottom of the card.
The book, both ways
ILLUSTRATIVE MODELBest ask 100.10, best bid 99.90. None of these prices are a real market — they are a model of the mechanism. Press Place a market order.
A market order is executed immediately, at the best price currently available. That is the whole promise and it is also the whole limit: speed is what you bought, and the exact number you pay is whatever is standing at the front of the book when the engine reaches your order. Nobody paired it by hand — the matching engine brings compatible buy and sell orders together automatically.
A limit order fixes the price at which you will buy or sell. You get the price limit and you give up the guarantee of execution: if the market never comes back to your number, the order simply sits in the book and can expire unexecuted. Your price, or no trade. The market order makes the opposite swap — instant execution, no say in the number. Neither one is the better order; they serve different intentions.
The definition
Three readings of the same screen.
Tap each card for what the book is actually telling you.
Hands on
Low liquidity. Now how big is your order?
Drag the size of your market order up — measured against the supply actually available in the book — and watch the execution change underneath it.
Small order
With low liquidity, large market orders move the price more, run through several price levels and produce slippage — execution is simply not always perfect at the displayed price. Spreads in a thin market tend to be wider, not tighter.
The bridge
Three parts, and the thing that decides how well they work.
Every trade you place walks this line, in this order.
Order, order book, matching engine — with liquidity quietly deciding how well the whole thing works out for you. That gap between the price you expected and the price you got is a subject of its own. Before it, though, comes the structural question underneath every trade you just placed: centralised or decentralised — who runs the venue, and what changes when nobody does. That is the next lesson.
Check yourself
Five questions.
Answers come straight from this lesson. Submitting completes it.