From the street it looks like a take-away street food kiosk only, but if you want in and through the kitchen to the left, you find the restaurant, most of which is upstairs. It's a simple and relaxed restaurant compared to most of the popular options.
I ordered the margherita con bufala, which was really delicious. I do wish there had been more tomato sauce though.
"At Di Matteo, on the Via dei Tribunali in the old historic center of Naples, the dining rooms are upstairs but the action is on the street. Pizza fritta (fried pizza) and pizza a portafoglia (folded “wallet” style) are sold from the takeout counter, befitting a pizzeria that doubles as a friggatoria (fried-food shop). The baked pizzas are prepared in rapid succession by the two pizzaioli who shape them and a third who works the turquoise-tiled, wood-fired oven. The fried pizzas are often assembled by Salvatore Di Matteo himself. He seals cheese, tomato, ham, and other fillings between two flattened rounds of pizza dough and lowers the package into a vat of hot oil. Out comes pizza fritta ripieno (fried stuffed pizza)—a fluffy, delicately crisp saucer of golden goodness.
What to order: Bufalina DOP; Pizza Fritta " - Evening Standard