Preheat the oven to 375°F (190°C), and line a baking tray with either foil or parchment paper to simplify cleanup.
Spread the crackers evenly in a single layer across the prepared baking sheet.
Add a small dollop (roughly ½ teaspoon) of pizza or marinara sauce onto the center of each cracker.
Distribute the shredded mozzarella evenly over the top of the sauce, aiming for about 1 to 2 teaspoons per cracker, depending on size.
Place one mini pepperoni slice—or a few chopped pieces—on top of the cheese layer for each cracker.
Dust the tops lightly with the Italian seasoning, and if desired, sprinkle additional toppings such as Parmesan, oregano, or red pepper flakes.
Slide the tray into the oven and bake for 6 to 8 minutes, or until the cheese has melted and started to bubble.
Allow the bites to rest for 2 minutes after baking, then serve while still warm.