Coat the shrimp evenly with oil or spray in a mixing bowl.
Sprinkle garlic powder, salt, and black pepper onto the shrimp and toss again for full coverage.
Place the shrimp in a single layer inside the air fryer basket.
Cook at 400°F for 8 to 14 minutes, shaking the basket and turning the shrimp halfway through to ensure even air frying.
Remove shrimp from the air fryer and transfer to a serving bowl.
Squeeze fresh lemon juice over the shrimp and garnish with parsley or chili flakes if desired before serving hot.