Prep the drumsticks: Pat the chicken very dry with paper towels.
Dry skin means better browning and crisping.
Season: In a large bowl, toss drumsticks with olive oil, salt, pepper, garlic powder, onion powder, paprika, and chili powder if using. Rub well to coat evenly.
Preheat the air fryer: Set your air fryer to 380°F (193°C) for 5 minutes. A hot basket helps prevent sticking and speeds up crisping.
Air fry, round one: Arrange drumsticks in a single layer, leaving space between them.
Cook at 380°F for 18–20 minutes, flipping halfway. They should start to brown and the skin should look rendered.
Brush with BBQ sauce: Mix 3/4 cup BBQ sauce with the vinegar or lemon juice if using. Brush generously over all sides of the drumsticks.
Air fry, round two: Increase heat to 400°F (204°C).
Cook for 4–6 more minutes, flipping once and brushing with a little more sauce. You want the sauce to caramelize and get glossy.
Check doneness: Use an instant-read thermometer. The thickest part should reach 165°F (74°C), but for drumsticks, 175–185°F often tastes better and stays juicy since the connective tissue breaks down more.
Rest and serve: Let the chicken rest 5 minutes.
Brush with the remaining BBQ sauce if you like it extra saucy. Garnish and serve warm.