Everyone is aware that web applications are getting bigger and more popular, but as they evolve, web applications need to get better and more modern. This thesis looks at various aspects of modern web applications. In the next chapters, analyses and evaluations of new technologies in web applications in terms of frontend and backend are presented, as well as common requirements and challenges, which also need to be taken into account. Furthermore, the thesis also contains an analysis of quality factors of web applications and deals with how quality can be ensured so that the finished product – the web application – is good, efficient, functional and that the users are satisfied. In addition, the design of the communication and other settings between the client and the web server will also be debated to ensure that the communication between them is secure, as well as the mathematical principles that are the basis of today’s security.