Abstract: A computer-implemented method for facilitating presentment and payment of bills or invoices related to consumption of products and services between a biller and a payer via an online payment portal over a communication network is provided. A template is generated that defines terms and conditions related to payment of a bill or invoice. The terms and conditions are accepted by the payer and the payer's financial institution and received from the biller. One or more rules are derived from data related to the terms and conditions defined in the template. The derived one or more rules are applied on the bill or invoice associated with the template to derive processing logic. Payment of the bill or invoice made by the payer is processed using the derived processing logic.