In a decentralized market, your orders reach liquidity through your broker.
How the broker handles them, where they are routed, how fast they are filled and what it charges, directly affects the price you get and what each trade costs.
In an A-Book model, the broker passes your orders to external liquidity providers, such as banks.
The broker earns from a spread markup or a commission, so its income depends on how much you trade, not on whether you win or lose.
In a B-Book model, the broker takes the other side of your trade internally. Fills can be fast and consistent, but the broker's result depends partly on its clients' results.
That is why regulation and transparency matter so much here.
Many brokers use both models. Smaller or short-term orders may be handled internally, while larger flow is passed to liquidity providers.
Ask how your orders are executed. A regulated broker will explain its execution policy.
The lowest spread isn't always the cheapest account. Compare the total cost of the same trade, including commission.
Know how your broker executes, and what you actually pay per trade.
