Preheat the air fryer to 380°F (193°C).
Wash and dry all vegetables thoroughly.
Cut the vegetables into uniform-sized pieces for even cooking.
Place the bell pepper, zucchini, broccoli, cauliflower, mushrooms, and red onion into a large mixing bowl.
Drizzle with olive oil.
Sprinkle with garlic powder, sea salt, and black pepper.
Toss until all vegetables are evenly coated.
Arrange the vegetables in a single layer in the air fryer basket.
Avoid overcrowding and cook in batches if necessary.
Air fry for 8 minutes.
Shake the basket halfway through cooking.
Continue cooking until vegetables are tender and lightly browned around the edges.
Serve immediately while warm