Hosting models
Blazor has two different hosting models. The first hosting model that Microsoft released is the Blazor Server model. In this hosting model, the web app is executed on the server. The second hosting model that Microsoft released, and the topic of this book, is the Blazor WebAssembly model. In this hosting model, the web app is executed on the browser.
Each hosting model has its own advantages and disadvantages. However, they both use the same underlying architecture. Therefore, it is possible to write and test your code independent of the hosting model. The major differences between the two hosting models concern latency, security, data access, and offline support.
Blazor Server
As we just mentioned, the Blazor Server hosting model was the first hosting model released by Microsoft. It was released as part of the .NET Core 3 release in September 2019.
The following diagram illustrates the Blazor Server hosting model: