A method for processing a payment transaction implemented by an autonomous electronic device for processing payment transactions, called a payment kiosk. The payment kiosk includes a processor connected to at least one rendering device for rendering offers of items or services being vended and linked to at least one communications interface and to at least one contactless payment terminal. The a method includes: transmission, by a browser installed within the payment kiosk, of a request for obtaining contents made to a contents server; reception, by the browser, coming from the contents server, of an HTML content including at least one payment tag; processing the HTML content, delivering a view of the HTML content on the at least one rendering device; and preparation, by anticipation, by the contactless payment terminal, of at least one payment transaction as a function of data attributes of the at least one payment tag.