A computer-implemented method presents on a merchant checkout graphical user interface associated with a payment processor widget. The payment processor widget determines affiliations of a plurality of accounts and a plurality of issuers of a user. The payment processor widget via the merchant checkout graphical user interface defines at least one selectable graphic configured for receiving interactions of the user on the selectable graphic. In response to receiving the selection of the selectable graphic, the payment processor widget presents a field within the merchant checkout graphical user interface for receiving a credential from the user associated with an authentication widget of the particular issuer. The authentication widget communicates the credential to the particular issuer for authentication of the user. In response to receiving a successful authentication indicator from the particular issuer, the payment processor widget displays a message indicating that a transaction was approved.