Execution is the fulfillment of a trading order through one or more completed trades. An accepted or submitted order has not necessarily executed: it may remain open, be rejected later or expire without a fill.
How an order becomes a trade
In an order-book market, a matching engine pairs compatible buying and selling interest under the venue’s rules. A single order may fill at several prices and in several quantities. In an automated market maker, a swap executes against pool liquidity through smart-contract rules rather than matching individual resting orders.
A market order seeks available execution but does not guarantee the price seen when it was submitted. A limit order constrains the acceptable price but may never fill. Available liquidity, order priority, technical delays and any protection limits all affect the outcome.
Reading execution results
The filled quantity and actual fill prices describe what traded. For multiple fills, a quantity-weighted average price summarizes the execution; fees may be reported separately. Canceling an unfilled remainder does not normally undo fills already completed.
Execution is distinct from settlement, which fulfills the resulting payment or delivery obligations. On-chain execution also needs to be distinguished from submission and finality. A fast response confirming receipt alone is not proof of a completed trade.