Better browsers and new features enabled a shift from server-side rendered web applications to browser-rendered web applications, where all presentation logic and most business logic is executed in the browser. This thesis will survey three web applications paradigms by example of electronic banking: (1) traditional software installations, (2) server-rendered web apps, and (3) browser-based web apps. The goal is to identify pros and cons of each paradigm and it's security implications, as well as security best practices for browser-based web apps.