is the backing made of rubber or polyester? Will it stain vinyl floors?

Hello, Thank you for reaching out! This mat has a rubber backing and is made for an outdoor space. While all Mohawk Home products have been tested and approved for use on Mohawk flooring, we cannot guarantee the safety of our mats or rugs on other types of flooring. The safest thing to do would be to contact your flooring manufacturer to make sure that this product is approved for use.