Method and system for authorizing and processing payment transactions over a network

Computer-implemented method for authorizing and processing payment transactions over a network, the payment transactions being for a purchase order to be paid from a user's financial account, the method comprising:

• a) initiating, responsive to a user payment request to process a payment transaction for a purchase on a merchants web site, a user interface;
• b) establishing, by the user interface responsive to the user payment request, a secure communication channel with an account server, the account server having stored a profile of an registered user of an financial account;
• c) submitting, by the user interface, purchase information of the purchase order to the account server;
• d) requesting, by the account server through the user interface, authentication of the user;
• e) linking, at the account server, purchase information to the user profile;
• f) requesting, through the user interface, purchase confirmation by the user;
• g) requesting, by the user interface responsive to the purchase confirmation, a checkout reference for the confirmed purchase order from the account server;
• h) submitting, by the user interface, at least part of the purchase information and the checkout reference to a payment service provider to process the payment transaction.