Blazor

Overview

Blazor is a web framework that enables developers to build interactive web user interfaces using C# and .NET, rather than JavaScript. Introduced by Microsoft in 2018, it is integrated into the broader ASP.NET Core ecosystem, providing a consistent development experience for .NET developers across client and server-side logic Blazor documentation. The framework supports multiple hosting models, allowing applications to run directly in the browser via WebAssembly or on the server with real-time communication via SignalR.

Blazor targets developers proficient in C# and .NET who seek to extend their skills to web development without introducing additional JavaScript frameworks. It offers a component-based architecture similar to other modern frontend frameworks, where UI elements are encapsulated into reusable components written in C#, HTML, and CSS. This approach is intended to simplify development by allowing a single language for both frontend and backend logic, which can lead to reduced context switching and improved code reusability within a .NET environment Blazor homepage.

There are several hosting models available for Blazor applications:

• Blazor WebAssembly (Wasm): This model executes C# code directly in the browser using WebAssembly. The application and its dependencies are downloaded to the client, and the C# code runs client-side, enabling offline capabilities and reduced server load after initial download Blazor WebAssembly hosting documentation.
• Blazor Server: In this model, the application executes on the server within an ASP.NET Core app. UI updates, event handling, and JavaScript interop calls are handled over a SignalR connection, which is a real-time communication framework for ASP.NET Core. This approach benefits from smaller download sizes and leverages server resources for processing Blazor Server hosting documentation.
• Blazor Hybrid: This model allows Blazor components to be integrated into native client applications, such as .NET MAUI, WPF, and Windows Forms. The components run natively in an embedded web view, combining the interactive web UI capabilities of Blazor with native device features Blazor Hybrid documentation.

Blazor is particularly suited for organizations and teams with existing investments in the .NET ecosystem and a preference for C# as a primary development language. It provides a path to building modern, interactive web applications, as well as desktop and mobile applications, all within a unified technology stack. While other frameworks like React, Angular, and Vue.js dominate the JavaScript-centric frontend landscape, Blazor provides an alternative for developers seeking to avoid JavaScript for client-side logic WebAssembly on MDN. Its integration with ASP.NET Core also makes it a strong contender for full-stack C# development projects.

Key features

• Component-based UI: Build UIs with reusable, interactive components written using C#, HTML, and CSS. This modular approach supports clear separation of concerns and facilitates maintainability Blazor components documentation.
• C# for client-side logic: Execute C# code directly in the browser via WebAssembly (Blazor WebAssembly) or on the server (Blazor Server), eliminating the need for JavaScript for client-side interactivity Blazor website.
• Multiple hosting models: Supports Blazor WebAssembly for client-side execution, Blazor Server for server-side execution, and Blazor Hybrid for embedding web components in native apps Blazor hosting models overview.
• JavaScript interop: Provides mechanisms to call JavaScript functions from C# and C# methods from JavaScript, enabling integration with existing JavaScript libraries and browser APIs when necessary Blazor JavaScript interop.
• Integrated with .NET ecosystem: Leverages the full power of .NET, including existing .NET libraries, tooling, and the ASP.NET Core framework, for a unified development experience Blazor homepage.
• Forms and validation: Includes built-in support for handling forms and input validation, simplifying the process of collecting and validating user data Blazor forms and validation documentation.
• Routing: Offers client-side routing capabilities to manage navigation within single-page applications without full page reloads Blazor routing documentation.
• Dependency Injection: Fully supports the dependency injection pattern, facilitating testability and modular design Blazor dependency injection.

Pricing

As of May 7, 2026, Blazor is an entirely free and open-source framework developed and maintained by Microsoft. There are no licensing fees, usage costs, or paid tiers associated with using Blazor itself. Developers can utilize the .NET SDK and all Blazor features without charge Blazor homepage.

Common integrations

• ASP.NET Core Identity: For user authentication and authorization, Blazor applications often integrate with ASP.NET Core Identity, providing a robust security system ASP.NET Core Identity documentation.
• Entity Framework Core: For data access and object-relational mapping (ORM) with various databases, Entity Framework Core is commonly used with Blazor server-side applications Entity Framework Core documentation.
• SignalR: Blazor Server applications inherently use SignalR for real-time communication between the client and server. It can also be used in Blazor WebAssembly for real-time features ASP.NET Core SignalR documentation.
• OpenID Connect / OAuth 2.0 Identity Providers: Blazor supports integration with external identity providers for authentication using OpenID Connect and OAuth 2.0 protocols Blazor authentication with Azure AD B2C.
• JavaScript libraries: Through its JavaScript interop features, Blazor can integrate with any existing JavaScript library, such as charting libraries (e.g., Chart.js) or UI component frameworks Blazor JS interop documentation.
• Third-party UI components: Various vendors offer commercial and open-source UI component libraries specifically designed for Blazor, such as Telerik UI for Blazor or Radzen Blazor Components Third-party Blazor UI components.

Alternatives

• React: A JavaScript library for building user interfaces, often used for single-page applications, focusing on declarative components.
• Angular: A comprehensive, TypeScript-based framework for building scalable web applications, offering a complete solution for client-side development.
• Vue.js: A progressive JavaScript framework for building user interfaces, known for its approachability and performance, often adopted incrementally.
• Svelte: A compiler that converts Svelte components into highly optimized vanilla JavaScript at build time, eliminating the need for a runtime framework.
• Next.js: A React framework for building full-stack web applications, offering features like server-side rendering and static site generation for improved performance and SEO.

Getting started

To begin developing with Blazor, you need to install the .NET SDK. Once installed, you can create a new Blazor project from the command line. The following example demonstrates how to create a new Blazor WebAssembly app, which is a common starting point for client-side Blazor development:

dotnet new blazorwasm -n MyBlazorApp
cd MyBlazorApp
dotnet run

This sequence of commands will:

1. dotnet new blazorwasm -n MyBlazorApp: Create a new Blazor WebAssembly project named MyBlazorApp.
2. cd MyBlazorApp: Navigate into the newly created project directory.
3. dotnet run: Build and run the application. By default, it will launch on a local web server (typically https://localhost:5001 or http://localhost:5000), which you can then open in your web browser.

The new project will include a basic Blazor application with a counter component, a fetch data component, and navigation. You can then open the project in an IDE like Visual Studio or Visual Studio Code to begin modifying the C# and Razor components.