Blazor

Overview

Blazor is a web UI framework developed by Microsoft, introduced in 2018, that allows developers to create interactive client-side web applications using C# and .NET. This approach contrasts with traditional web development, which typically relies on JavaScript for client-side logic. Blazor applications can run in various configurations, offering flexibility in deployment and execution environments.

One primary hosting model is Blazor WebAssembly, where the C# code, .NET runtime, and application are downloaded to the browser and executed directly on the client side. This enables true single-page application (SPA) experiences without server round-trips for UI updates, similar to JavaScript-based frameworks. Another model is Blazor Server, where the C# code executes on the server, and UI updates are sent over a SignalR connection to the client. This model can reduce the initial download size and leverage server resources more directly.

Blazor is suited for developers and teams already invested in the .NET ecosystem, providing a unified language and framework for both frontend and backend development. It supports building complex SPAs, progressive web applications (PWAs), and even desktop applications through Blazor Hybrid, which embeds Blazor components in native client apps using platforms like .NET MAUI, WPF, or Windows Forms. This versatility makes Blazor a candidate for projects requiring consistent tooling and language across different application layers and platforms.

For technical buyers, Blazor offers the potential for increased developer productivity for C# teams by eliminating the need to context-switch between C# for the backend and JavaScript for the frontend. Its integration with the broader .NET platform means access to a mature ecosystem of libraries, tools, and established development practices. The choice between Blazor WebAssembly and Blazor Server allows for optimization based on specific application requirements, such as client-side performance, initial load times, or server resource utilization. The framework's open-source nature further contributes to its appeal, providing transparency and community support, as detailed in the Blazor homepage.

Key features

• C# for Frontend Development: Enables building interactive web UIs using C# and .NET, eliminating the need for JavaScript for client-side logic.
• Component-Based Architecture: Facilitates building UIs from reusable, self-contained components, promoting modularity and maintainability.
• Multiple Hosting Models: Supports Blazor WebAssembly (client-side in browser), Blazor Server (server-side rendering with SignalR), and Blazor Hybrid (embedding in native apps).
• .NET Ecosystem Integration: Provides access to the full .NET API, libraries, and tooling, streamlining full-stack development.
• Interoperability with JavaScript: Allows calling JavaScript functions from C# and C# methods from JavaScript, enabling integration with existing JavaScript libraries and browser APIs as described in the Blazor JavaScript Interop documentation.
• Routing and Layouts: Includes built-in routing capabilities to navigate between different pages and support for shared layouts across the application.
• Form Validation: Offers features for handling user input and performing client-side form validation.
• Progressive Web App (PWA) Support: Can be used to build PWAs, enabling offline capabilities and app-like experiences.
• Hot Reload: Provides hot reload functionality during development, allowing changes to be applied to the running application without a full restart.

Pricing

Blazor is an open-source framework developed by Microsoft and is provided free of charge. There are no licensing fees, usage costs, or paid tiers associated with using Blazor itself.

While Blazor itself is free, developers may incur costs related to hosting Blazor applications (e.g., cloud hosting services like Azure, AWS, or GCP), development tools (e.g., Visual Studio Enterprise licenses for advanced features, though Visual Studio Community is free), or third-party components and services integrated into a Blazor application. The core framework and its SDKs are available without cost, as stated on the Blazor product page.

Common integrations

• ASP.NET Core: Blazor integrates with ASP.NET Core for server-side logic, API development, and hosting, forming a full-stack .NET solution. Consult the official Blazor documentation for details on hosting models.
• Entity Framework Core: For data access, Blazor applications often integrate with Entity Framework Core to interact with relational databases using C# objects.
• Azure Services: As a Microsoft technology, Blazor applications frequently integrate with Azure services for hosting, authentication (e.g., Azure Active Directory), databases (e.g., Azure SQL Database), and other cloud capabilities.
• JavaScript Libraries: Despite using C# for UI, Blazor supports JavaScript interoperability, allowing integration with existing JavaScript libraries and frameworks. The Mozilla WebAssembly documentation provides context on how WebAssembly-based frameworks can interact with JavaScript.
• Authentication & Authorization: Blazor integrates with ASP.NET Core Identity and other authentication providers for securing web applications.
• SignalR: Blazor Server applications use SignalR for real-time communication between the server and client, enabling interactive UI updates.
• .NET MAUI: For Blazor Hybrid applications, Blazor components can be embedded within .NET MAUI applications to target mobile and desktop platforms.

Alternatives

• React: A JavaScript library for building user interfaces, maintained by Meta and a community of individual developers and companies.
• Angular: A TypeScript-based open-source web application framework led by the Angular Team at Google and a community of individuals and corporations.
• Vue.js: An open-source JavaScript framework for building user interfaces and single-page applications.
• Svelte: A free and open-source JavaScript framework that compiles components into small, vanilla JavaScript modules at build time.

Getting started

To create a new Blazor WebAssembly application, you need the .NET SDK installed. This example demonstrates creating a new project and running it.

# Install the latest .NET SDK (if you haven't already)
dotnet --version

# Create a new Blazor WebAssembly project
dotnet new blazorwasm -n MyBlazorApp

# Navigate into the project directory
cd MyBlazorApp

# Run the application
dotnet watch run

This command sequence will create a new Blazor WebAssembly project named MyBlazorApp, restore its dependencies, and then launch it in watch mode, which automatically recompiles and refreshes the browser when code changes are detected. The application will typically be accessible at https://localhost:5001 or http://localhost:5000.