Key points
- A market order prioritizes execution, not a guaranteed price.
- A limit order controls price but may not fill.
- Thin liquidity can increase slippage.
- Compare execution context, not only headline fees.
What an order instruction really says
A market order generally asks for immediate execution against available liquidity. It does not promise the last displayed price. A limit order sets a price condition, but it can remain unfilled if the market does not reach available liquidity at that level.
On fast or thin markets, the difference between displayed quotes and completed execution can matter more than a small fee difference.
Liquidity and order-book depth
Top-of-book quotes show only the best available prices, not how much size exists behind them. Larger orders can consume multiple price levels. That movement through the book is one source of slippage.
When comparing venues, look for transparent order-book mechanics and understand whether your chosen interface routes to an order book, an instant-buy quote or another execution model.
Use realistic test sizes
A platform can look cheap for a tiny sample trade and expensive for the size you actually use. Compare the same asset, order type and approximate size across venues, and consider the cost of moving assets afterward.
Execution quality can vary over time, so a single screenshot should not be treated as a permanent ranking.
Primary reading
These official sources provide background for the risk and custody concepts used in this guide. Product-specific facts should still be checked against the relevant operator and jurisdiction.