Preheat your air fryer to 200°C (390°F) to ensure even and quick roasting.
Place the green beans in a mixing bowl and drizzle with olive oil, tossing gently until all are evenly coated.
Sprinkle the garlic powder and salt over the beans, then toss again to distribute the seasonings evenly.
Spread the seasoned green beans in a single layer inside the air fryer basket, avoiding overcrowding for maximum crispness.
Cook for about 8–10 minutes, shaking the basket halfway through to promote even browning and charred edges.
Check the beans—they should be deep green with some browned spots and feel crisp when you bite into them.
If you prefer them crunchier, continue air frying for another 2 minutes, watching carefully to prevent burning.
Once done, transfer the roasted green beans to a serving dish and sprinkle with a little extra salt or lemon zest if desired for brightness.