Blazor WebAssembly Tutorial for Beginners: Build Your First C# App in 2025

Step-by-step guide to creating interactive web apps with C# in the browser

Updated 04 Oct 2025

If you're dipping your toes into modern web development and love the power of C#, then Blazor WebAssembly might just be your new best friend. In this Blazor WebAssembly tutorial for beginners, we'll walk through everything you need to build your first C# app in 2025. Whether you're coming from traditional web tech or you're a .NET enthusiast looking to go full-stack in the browser, this step-by-step guide covers the essentials: from setup and core components to deployment. By the end, you'll have a working Blazor WASM app that's ready to shine on the web.

Blazor WASM has exploded in popularity because it lets you write interactive client-side apps using C# instead of JavaScript. No more juggling languages or wrestling with DOM manipulation. It's all about leveraging the .NET ecosystem right in the browser, making it a game-changer for developers in 2025.

What Is Blazor WebAssembly and Why Choose It in 2025?

Blazor WebAssembly, or Blazor WASM for short, is a framework from Microsoft that runs .NET code directly in the browser via WebAssembly. This means you can build rich, responsive web apps with C# and .NET libraries, without ever touching JavaScript (unless you want to). It's perfect for beginners who want to stay in their comfort zone while creating modern web experiences.

In 2025, with .NET 9 and beyond pushing boundaries, Blazor WASM stands out for its performance boosts and seamless integration with tools like Visual Studio. It's ideal for single-page applications (SPAs), progressive web apps (PWAs), and even hybrid setups with Blazor Server. Plus, it aligns with the rise of cross-platform development, letting you share code between web, mobile, and desktop.

If you're tired of context-switching between frontend and backend languages, this Blazor tutorial will show you how to build a full C# app that feels native to the web.

Prerequisites for Your Blazor WASM Journey

Before we dive into the Blazor WebAssembly tutorial, let's make sure you're set up. You don't need a supercomputer, but a few basics will smooth the ride:

.NET SDK: Grab the latest version (at least .NET 8, but aim for .NET 9 in 2025) from the official Microsoft site. This powers your Blazor WASM projects.
Visual Studio 2022 or later: The Community edition is free and includes Blazor templates. If you prefer lighter tools, Visual Studio Code with the C# extension works great.
A modern browser: Chrome or Edge for testing your app.
Basic C# knowledge: If you're new to C#, no sweat. This guide assumes beginner level and explains key concepts.

Install the .NET SDK first, then fire up Visual Studio. Verify everything by running `dotnet --version` in your terminal. You're good to go!

Step 1: Setting Up Your First Blazor WASM Project

Let's get hands-on with creating your Blazor WebAssembly app. Open Visual Studio and select "Create a new project." Search for "Blazor WebAssembly App" and pick the standalone template (no ASP.NET Core hosted for now, to keep it simple).

Name your project something like "MyFirstBlazorApp" and hit Create. Visual Studio will scaffold everything: pages, components, and the basic routing setup. Run it by pressing F5, and boom, your app loads in the browser at localhost: something. You'll see a default counter and fetch data demo. That's your first C# app running in the browser via Blazor WASM!

Under the hood, the project includes key folders like Pages for Razor components and wwwroot for static assets. The Program.cs file bootstraps the app with dependency injection, just like a console app but for the web.

Pro tip: If you're using VS Code, install the .NET CLI templates with `dotnet new install BlazorWebAssembly.Cli` and create via `dotnet new blazorwasm`.

Step 2: Understanding Blazor Components: The Building Blocks

At the heart of any Blazor WASM tutorial are components. These are reusable pieces of UI built with Razor syntax, blending HTML and C# in .razor files. Think of them as custom HTML elements with logic.

@page "/counter"

<h1>Counter</h1>

<p>Current count: @currentCount</p>

<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>

@code {
    private int currentCount = 0;

    private void IncrementCount()
    {
        currentCount++;
    }
}

Here, `@page` sets the route, `@onclick` wires up events, and the `@code` block holds your C# logic. It's all compiled to WebAssembly, so it runs blazing fast.

Components can be nested: parent ones pass data to children via parameters like `<MyChildComponent Value="@someData" />`. This makes building complex UIs straightforward, even for beginners in modern web development.

Step 3: Building a Simple Blazor WASM App: A Todo List Example

Time to build something real. Let's create a basic todo list app in our Blazor WebAssembly project. This will showcase data binding, events, and lists, key skills for any C# web app.

First, add a new Razor component: Right-click Pages, add Component, name it TodoList.razor.

@page "/todos"

<h3>My Todo List</h3>

<input @bind="newTodo" placeholder="Enter a todo" />
<button @onclick="AddTodo">Add</button>

<ul>
    @foreach (var todo in todos)
    {
        <li>@todo</li>
    }
</ul>

@code {
    private string newTodo = string.Empty;
    private List<string> todos = new();

    private void AddTodo()
    {
        if (!string.IsNullOrWhiteSpace(newTodo))
        {
            todos.Add(newTodo);
            newTodo = string.Empty;
        }
    }
}

This uses two-way binding with `@bind` for the input, a loop for the list, and an event handler to add items. Navigate to /todos in your browser, add some todos, and watch the magic. You've just built an interactive C# app with Blazor WASM!

To make it more robust, you could add delete buttons or persist data with local storage via the IJSRuntime service. But for beginners, this nails the basics.

Handling Routing and Navigation in Blazor WASM

Blazor's built-in router makes navigation a breeze. In App.razor, you'll see `<Router AppAssembly="@typeof(App).Assembly">` which handles URL-based routing. Add links with `<NavLink href="/todos">Todos</NavLink>` in your NavMenu.razor for easy site navigation.

In 2025, with improved prerendering, Blazor WASM apps load quicker, rivaling JavaScript frameworks like React.

Step 4: Deployment: Taking Your Blazor App Live

You've built it; now share it. For Blazor WebAssembly deployment, publish to a static host like Azure Static Web Apps, GitHub Pages, or Netlify. In Visual Studio, right-click your project, select Publish, and choose "Folder" or a web target.

The output is a wwwroot folder with your .dll files, index.html, and JS runtime. Upload that to your host. For production, enable AOT (Ahead-of-Time) compilation in .NET 8+ for even better performance.

Test on a real server, and tweak for HTTPS. Congrats: your first C# web app is online!

Wrapping Up: Your Path Forward in Blazor WASM

There you have it, a complete Blazor WebAssembly tutorial for beginners. From setup to deploying your first C# app in 2025, you've covered the core of modern web development with Blazor WASM. It's empowering to build browser apps without leaving .NET behind.

Next steps? Dive into state management with Fluxor, integrate APIs, or explore Blazor Hybrid for desktop/mobile. The community is thriving, with tons of resources on docs.microsoft.com and forums.

Grab your tools and start coding. What's your first Blazor project going to be? Share in the comments if you run into snags. Happy developing!