Preheat your air fryer to 380°F (193°C) for 3–5 minutes. A hot basket is what gives you that first sizzle and a crisp skin instead of a steamed one. (My air fryer doesn't have a preheat button — I just run it empty while I prep.)
Pat the sausages dry with paper towels. Surface moisture is the enemy of browning. This takes ten seconds and makes a real difference.
Lightly coat the links with the oil, if using. Sausages render their own fat, so this is strictly optional — I use it on leaner chicken sausage and skip it on fatty brats.
Arrange the links in a single layer with space between each one. Don't let them touch. Crowding traps steam, and steamed sausage comes out pale and soft no matter how long you cook it. Cook in batches if you have to.
Air fry for 10–12 minutes, flipping with tongs at the halfway mark. The flip is what gives you even, all-around browning instead of a dark bottom and a pale top.
Check the internal temperature with an instant-read thermometer. Fresh pork or beef sausage is done at 160°F measured at the thickest part. Poultry sausage needs 165°F. Color is not a reliable doneness test — always temp it.
Rest the sausages 2–3 minutes before cutting or serving. The juices redistribute as they rest, which is the difference between a juicy bite and a dry one.