There is no way to ensure 100% that you will never have a back order, however, there are some important decisions you can make in designing your product to minimize the likelihood and impact of back orders.
By offering standard products, from popular manufacturers, in standard size, in the most common colorways you will reduce your likelihood of having a back ordered product. Those products tend to have the most robust stock available from the most distributors.
However, if you plan on offering more unique products, fear not, we have a robust process for how to handle back orders when they do come up. You can learn about how we handle back orders right here.