Web application architecture describes the relationship between web app components (i.e. - user interfaces, databases, and middleware systems) and the way they interact with each other. In other words, it provides a structure for how the client and server are connected. Properly designed web application architecture ensures that all of your components interact properly and serves as a strong foundation for expanding the app in later rounds of development.
This is a companion discussion topic for the original entry at https://blog.crowdbotics.com/how-to-choose-the-best-architecture-for-your-web-application/