A system and method to use quick response (QR) codes encoded with merchant website t identification codes and session GUID to register a user or code scanner with a merchant server, login the user or code scanner with the merchant server, and complete a purchase of an item or service within a virtual shopping cart of the merchant server. A code scanner can scan a QR code displayed on a device connected to the internet. An application server can receive an identification code from the code scanner and then transmit data indicating form fields to be filled in on a merchant webpage. A user profile can include data regarding the user and a payment instrument. The user profile data can prepopulate the form fields and the form field data can be transmitted to the merchant server to use for logging in the user and completing the purchase.