Preheat your air fryer to 375°F (190°C).
In a large bowl, whisk together flour, water, garlic powder, onion powder, salt, and pepper until smooth.
Toss the cauliflower florets into the batter until well coated.
Place the battered cauliflower in the air fryer basket in a single layer (work in batches if needed).
Air fry for 15 minutes, shaking halfway through for even crisping.
Meanwhile, mix buffalo sauce with melted butter (if using).
Transfer the crispy cauliflower to a bowl and toss with the buffalo sauce mixture.
Return the coated cauliflower to the air fryer for another 5 minutes.
Serve hot with ranch or blue cheese dressing for dipping!