Razor vs Blazor in .NET: What's the Difference?

When diving into modern web development using Microsoft technologies, it's easy to get confused between Razor and Blazor—two powerful tools in the .NET ecosystem. Though they share a similar name and syntax, their purposes, use cases, and behaviors are distinctly different.

In this post, we’ll unpack what each of them does, how they differ, and when to use one over the other.

What is Razor?

 Razor is a templating syntax that allows you to seamlessly embed C# code within HTML. It's primarily used in ASP.NET MVC and ASP.NET Core MVC applications to create server-rendered HTML views.

Razor makes it easier to generate dynamic content without writing raw HTML strings or using clunky code-behind logic.

Example Razor Code (in a .cshtml file):

<h2>Welcome, @Model.Username!</h2>
<p>Today's date is @DateTime.Now.ToLongDateString()</p>

 Key Characteristics of Razor:

1. Files have the extension .cshtml
2. Runs on the server.
3. Generates HTML that is sent to the browser.
4. Best suited for traditional server-rendered websites.
5. Limited client-side interactivity without JavaScript.

 What is Blazor?

Blazor is a modern web UI framework that allows developers to build interactive, client-side web apps using C# instead of JavaScript. It utilizes Razor syntax for its components, but it’s more than just a templating engine—it’s a full-fledged single-page application (SPA) framework.

There are two main hosting models for Blazor:

1. Blazor Server—The UI is rendered on the server, with UI updates sent via SignalR.

2. Blazor WebAssembly (WASM)—Runs entirely in the browser using WebAssembly.

 Example Blazor Code (in a .razor file):

<h3>Hello, @name!</h3>

<input @bind="name" placeholder="Enter your name" />
<button @onclick="SayHello">Greet</button>

@code {
    private string name = "Guest";

    private void SayHello()
    {
        Console.WriteLine($"Hello {name}!");
    }
}

Key Characteristics of Blazor:

1. Files have the extension .razor

2. Uses C# on both client and server.

3. Component-based architecture.

4. Supports real-time DOM updates and rich interactivity.

5. There's no need for JavaScript for most tasks.

Razor vs Blazor: Feature Comparison

 When Should You Use Razor or Blazor?

✅ Use Razor when:

1. You're building a traditional web application.

2. SEO and server-side rendering are crucial.

3. You prefer simplicity and minimal client-side logic.

✅ Use Blazor when:

1.   You want a modern SPA experience without relying on JavaScript.
2.   You’re building rich, dynamic UIs with real-time interactions.
3.   You want to reuse C# code on both the server and the client.

Final thoughts

While Razor and Blazor share a similar syntax and naming style, they cater to different architectural needs. Razor is a solid choice for server-rendered applications with minimal client interactivity, while Blazor unlocks the full power of C# for building modern, interactive web applications—all without touching JavaScript.

As the .NET ecosystem continues to evolve, Blazor is emerging as a strong contender for building full-fledged web apps using only .NET technologies.

Whether you choose Razor or Blazor depends on your project’s goals, but understanding both will make you a more versatile developer.

Have questions or want to share your experience with Razor or Blazor? Drop a comment below!