Open theme builder and API

Methods and system for customizing a webpage include generating a schematic representation of the webpage wherein the webpage includes a plurality of section elements that are customizable. The schematic representation identifies a plurality of schematic section elements corresponding to the plurality of section elements of the webpage. The schematic representation is rendered for the webpage and provides visual navigation through various section elements of the webpage. A schematic section element is selected from the schematic representation, for customizing. The selection of the schematic section element triggers rendering of respective one or more navigation links, which provide tools or options for customization. Changes representing customization to one or more attributes associated with the selected schematic section element are received and the attributes are updated at the schematic representation in real-time. The changes are cascaded to the corresponding section elements of the webpage in substantial real-time based on user interaction.