You click buy, and the trade feels instant. In reality, the order passes through several steps before it becomes a position on your account.

Each step takes time, even if it is only a fraction of a second, and that time is where the price can move against you or in your favour.

The Order Leaves Your Platform

Your platform sends the order to the broker's server first, not straight to the wider market. The broker checks the order, confirms you have enough margin, and then decides where it goes next.

From there it either routes out to a liquidity provider or fills against the broker's own book, depending on the account type and the size of the trade.

Market Execution vs Instant Execution

Under market execution, you set the size of the trade and accept whatever price is live when the order lands. There is no requote. The trade opens at the current price, even if that price has shifted slightly since you clicked.

Under instant execution, you request a specific price along with the size. If that price has already moved, the broker sends back a requote instead of filling the order, and you choose whether to accept the new price or cancel.

Where Latency Creeps In

Latency is the delay between you sending the order and it reaching the point where it gets filled. It builds up across several stages: your own connection, the platform's servers, and the path to the liquidity provider.

A few milliseconds rarely matters on a calm market. During a fast move, even a short delay can mean the price has already changed by the time your order arrives.

Slippage: Positive and Negative

Slippage is the gap between the price you expected and the price you actually got. Negative slippage means you paid more on a buy or received less on a sell. Positive slippage works the other way, giving you a better price than you expected.

Both happen most often during high volatility around news events, or when liquidity thins out and there are fewer prices on offer at any given moment. A market order is more exposed to slippage than a limit order, since a limit order only fills at your chosen price or better.

Why Order Size Matters

A small order usually fills at one price without any trouble. A large order can eat through several price levels in the order book, since there may not be enough volume sitting at the best price to cover the whole size.

When that happens, part of the order fills at the first price and the rest fills at a slightly worse one. The final average price you get is a blend of both, which is another form of slippage tied purely to size rather than speed.

What a Requote Looks Like

Say you request a price on instant execution and the market ticks up half a pip before your order arrives. The broker cannot fill you at the old price, so it sends back a new one and waits for your response.

You can accept the new price, reject it, or let the request time out. None of those choices happen instantly either, so a string of requotes in a fast market can cost you more time than the small price gap itself.

Why This Matters Beyond Forex

None of this is unique to currency pairs. what is cfd trading on shares and indices goes through the same steps, since those contracts also route through liquidity providers and pass through the same latency and slippage risks along the way.

Checking Execution Quality

Execution speed and slippage rarely show up on a pricing page, but they shape your actual results just as much as the spread does. Ask how orders route, how fast they typically fill, and how often clients see requotes.

A best CFD broker for your style of trading is one whose execution matches how you trade, not just one with the tightest advertised spread. A scalper feels latency far more than someone holding a position for weeks.

What You Can Control

You cannot remove slippage or latency, but you can reduce your exposure to them. Avoid placing large market orders right before major news releases, when liquidity often drops just as volatility spikes.

Use limit orders when the exact price matters more than getting filled instantly. That trade off, price certainty against speed, sits behind almost every order type you will come across.

Splitting a large order into smaller pieces can also reduce how much it moves the price against you. It takes a little more effort to manage, but it keeps any single fill from eating through several price levels at once.