Systems and methods are provided for enabling in-video shopping functionality that includes a cross-video shopping cart. For example, a user may add items to an electronic shopping cart that is persistent across two different websites or pages, where items may be added to the shopping cart within overlays on two separate videos presented on the respective pages. The persistent shopping cart features may also enable a persistent shopping cart that enables joint checkout involving two or more different payment processors, two or more different third-party shopping systems, two or more different publisher systems, two or more different video hosting platforms, or two or more different client devices sharing a user account.