A stop order on an option comes in two flavors, and the difference is the whole game when the tape is moving fast.

Stop-market: guaranteed exit, uncertain price

A stop-market becomes a market order the instant your stop price trades. It gets you out — but at whatever the market offers, which in a fast, wide 0DTE option can be meaningfully worse than your trigger (slippage). You're trading price certainty for exit certainty.

Stop-limit: guaranteed price, uncertain exit

A stop-limit becomes a limit order at your chosen price. You won't sell below your limit — but if the option gaps straight through it (very possible on 0DTE), the limit never fills and you're still holding a losing position that keeps falling. You protected the price and lost the protection.

On 0DTE, the risk isn't a few cents of slippage — it's a stop-limit that never fills while the option craters. Protection means getting out.

Which to use

For a fast-moving same-day option where the point of the stop is capital protection, a stop-market is usually the safer choice: a little slippage is a cheap price for actually exiting. A stop-limit makes more sense on calmer, more liquid positions where a bad fill is the bigger worry than a missed one. The failure mode to fear on 0DTE is the un-filled stop-limit. NoVo's exits lean toward guaranteed protection for exactly this reason — a stop that doesn't fire isn't a stop.