This is a busy location but they take allergy concerns seriously. Let the cashier know you an allergy order and they prepare your order separately and change gloves and mark it clearly on the receipt. I've eaten here twice since my celiac diagnosis and have not had a reaction. Everything on the menu except the buns are GF, so order your burger protein-style (lettuce-wrapped), but I would recommend ordering without onions and with sauce on the side (they'll give you packets of the special sauce) just to avoid cross-contamination because onions are flipped with buns and sauce could come from a shared container). I love ordering cheesy fries via the secret menu! Fries are from a dedicated fryer.