Blazor documentation

What Blazor is

Blazor is the part of ASP.NET Core for building interactive web UI in C# instead of a JavaScript framework. You write Razor components, .razor files that mix HTML and C#, and they can run on the server or in the browser through WebAssembly. Since .NET 8, dotnet new blazor creates a Blazor Web App where each page or component chooses a render mode.

What the documentation covers

• Render modes: static server rendering, Interactive Server (components run on the server and update the browser over a SignalR connection), Interactive WebAssembly (components run in the browser) and Interactive Auto, which starts on the server and switches to WebAssembly.
• Components: parameters, event callbacks, lifecycle methods, rendering, templated components, virtualisation and state across prerendering.
• Forms and validation: EditForm, the built-in input components and DataAnnotations validation, with support for nested objects and collections added in .NET 10.
• Security: authentication and authorisation for server and WebAssembly apps, including ASP.NET Core Identity in the project template.
• JavaScript interop: calling JavaScript from .NET and .NET from JavaScript when you need a browser API or library.
• Performance and hosting: rendering performance, WebAssembly download size, and deploying Blazor apps.
• Tutorials: step-by-step builds of a first Blazor app and a movie database app.

Is it worth your time?

If you chose Blazor, these docs are the best source available: the framework changed a lot in .NET 8 with the Blazor Web App and render modes, and many older tutorials describe the separate Blazor Server and Blazor WebAssembly templates that came before. Blazor roles are fewer than Angular or React ones, but they exist in Microsoft-focused companies, internal tools and government projects.

How to learn from it

Do the first app tutorial, then read the render modes article slowly, because it decides where your code runs and how it reaches data. Then work through components, forms and security while you build a small app on top of your own API. Read the performance pages before you build large tables.

Prerequisites

C# and ASP.NET Core basics, plus basic HTML and CSS. Blazor writes the markup for you, but layout and styling are still yours.

Free or paid?

Free. Blazor is part of the open source ASP.NET Core framework.

What you can do after it

Build a Blazor Web App with the right render mode per page, forms with validation, authentication, and components that work in both server and WebAssembly modes.