There are a lot of things going on in the background, when a Blazor WebAssembly application is being started. In some cases you might want to take a bit more control over that process. One example might be the wish to display a loading screen for applications that take some time for initial preparation, or when users are on a slow internet connection. However, in order to control something, we need to understand what is happening first. This article takes you down the rabbit hole of how a Blazor WASM application starts up.