In a mixing bowl, combine the boxed cake mix, eggs, vegetable oil, and water according to the instructions on the cake mix box. Use a whisk or electric mixer to ensure the batter is smooth and well-mixed. If you're adding optional mix-ins, fold them into the batter at this stage.

Lightly grease the cake pan or silicone mold that fits inside your air fryer basket with non-stick cooking spray. This will prevent the cake from sticking.

Pour the prepared cake batter into the greased cake pan, spreading it out evenly.

Carefully place the cake pan with the batter into the preheated air fryer basket.

To check if the cake is done, insert a toothpick or cake tester into the center of the cake. If it comes out clean or with just a few moist crumbs, the cake is ready. If not, continue cooking for a few more minutes and check again.

Once the cake is done, carefully remove the cake pan from the air fryer using oven mitts. Allow the cake to cool in the pan for a few minutes before transferring it to a wire rack to cool completely.

Once the cake has cooled, you can frost or decorate it as desired. Slice and enjoy your homemade air fryer cake!