Limit Order

A limit order says fill me at this price or better, or not at all. A buy limit at $63,500 will only execute at $63,500 or lower; until then it rests in the order book, waiting for the market to come to it.

The trade-off against market orders

You get price control: no slippage past your limit, and you may even capture the spread instead of paying it (maker fees are often lower, too). What you give up is certainty. The market may run away without ever touching your price, and the trades you miss this way are disproportionately the good ones, because strong moves don't pull back to fill patient buyers.

In backtesting

AlphaProve fills a resting limit when price trades through its level, at the limit price exactly. One honest simplification worth knowing about: on the first touch the engine fills the full remaining quantity, whereas real books sometimes fill you partially. That errs slightly optimistic on fill completeness while staying exact on price.

On AlphaProve

Because a resting limit adds liquidity rather than taking it, the cost model charges it the maker fee — a separate rate from the taker fee a crossing market order pays — so the same entry can show a different cost line depending on which order type placed it. Limit sits alongside market and stop as the three order types the engine simulates, and of the three only market and stop fills carry a slippage penalty.