The increasing complexity and popularity of web application and the movement of enterprise applications from desktop based to web based architecture have created sophisticated challenges yet the need for scalable modern web applications architecture. One way to manage this complexity is to design and develop the web application using single page architecture. The paper describes a single page web application architecture suitable for modern web application development using React JS for building the complex interactive user interfaces, Redux for handling state management, Redux Saga for handling side effects, Node JS as server-site scripting language, Immutable JS to handle immutability and Webpack for module bundling. It is aimed at facilitating the developers and business stakeholders to comprehend the need and importance of making application scalable and maintainable over time. [ABSTRACT FROM AUTHOR]