Overview
A cart collects what a visitor is about to buy, in one order per vendor. Create one with POST /carts, keep its url_key, then add, change and remove items, choose shipping and set the checkout address before checkout. Most cart endpoints work without a token: for a guest cart, the url_key alone gives access, so keep it private to the visitor. When a signed-in member calls a cart endpoint on a guest cart with a token, that cart, and the guest’s other carts and orders, are attached to the member’s account; from then on, reading the cart or changing its items requires that member’s token.