Provided are check-in to checkout systems and methods. The system includes a point of sale, a display, a mobile device, and a backend system. When the POS starts a transaction, such as, but not limited to scanning an item, the POS generates a transaction/basket identification. In response to starting the transaction, the POS sends the transaction/basket ID to the display in the form of a QR code or one-dimensional barcode. The mobile device operating a mobile application scans and captures the displayed code and reports to the backend systems. The backend systems then send a check-in event, which includes gathered data by the backend systems, to the POS and the POS acknowledges receipt of the message. At this point, a notification may be sent to the mobile application that the check-in was successful and a link is established for flow of information.