Blazor

Blazor lets C# developers build interactive web UIs without JavaScript. Blazor WebAssembly runs .NET code directly in the browser sandbox; Blazor Server keeps UI logic on the server and sends updates via SignalR. Blazor Auto (introduced in .NET 8) starts with Server rendering for fast initial load, then downloads the WASM runtime and switches to client-side execution. For .NET shops, Blazor eliminates the context switch between C# backend and JavaScript frontend.

Quick start

dotnet new blazor -n MyBlazorApp --interactivity WebAssembly
cd MyBlazorApp
dotnet run

@* Components/Counter.razor *@
@rendermode InteractiveWebAssembly

<h1>Counter</h1>
<p>Current count: @currentCount</p>
<button @onclick="IncrementCount">Click me</button>

@code {
    private int currentCount = 0;

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

@* Pages/FetchData.razor *@
@page "/weather"
@inject HttpClient Http

@if (forecasts == null)
{
    <p>Loading...</p>
}
else
{
    <table>
        @foreach (var f in forecasts)
        {
            <tr><td>@f.Date</td><td>@f.TemperatureC°C</td></tr>
        }
    </table>
}

@code {
    private WeatherForecast[]? forecasts;

    protected override async Task OnInitializedAsync()
    {
        forecasts = await Http.GetFromJsonAsync<WeatherForecast[]>("sample-data/weather.json");
    }
}

When to use

Blazor is ideal for .NET teams that want to build web UIs without switching to JavaScript. It’s particularly valuable for internal enterprise tools, line-of-business apps, and teams with deep .NET expertise. Blazor WASM suits offline-capable apps; Blazor Server is better for apps needing real-time data. If your team already uses React or Vue, sticking with the JavaScript ecosystem is usually the right call unless there’s strong motivation to unify the stack in C#.