The invention relates to an attachment mechanism and system used to accessorize, ustomize and/or personalize footwear with interchangeable uppers or straps, especially open shoes and sandals. More particularly, this invention presents a safe, secure and easy system for the attachment and detachment of shoe uppers and straps to shoes and sandals. This invention allows both the manufacturer and wearer to promote and display fashion and theme material of their own choosing, with the freedom to change the material or message without having to change footwear. The invention comprises a releasable fastener that connects a retainer, secured with the sole of the footwear, to an upper or strap. The releasable fastener is comprised of an upper and lower bar or metal loop, each loop carried on a barrel, the barrels interlocking with each other in a sliding engagement and held in the closed or engaged position by a magnet or by a biasing member.