The installation differs from the normal frontend getting started guide in the configuration of the .NET trace propagation. The _traceParentContext value is set based on the server trace context so that client side tracing can carry the existing trace ID and session context. Update your Components/App.razor HTML template entrypoint based on the following:

@using OpenTelemetry.Trace
<!DOCTYPE html>
<html lang="en">

<head>
    <meta name="traceparent" content="@_traceParentContext">
	<script src="https://unpkg.com/highlight.run"></script>
    <script>
        H.init('<YOUR_PROJECT_ID>', {
            serviceName: 'highlight-dot-net-frontend',
            tracingOrigins: true,
            networkRecording: {
                enabled: true,
                recordHeadersAndBody: true,
            },
        });
    </script>
    @* your standard head contents here... *@
</head>

<body>
	@* your standard body contents here... *@
	<Routes/>
	<script src="_framework/blazor.web.js"></script>
</body>

</html>

@code
{
    private string? _traceParentContext;

    // set the `traceparent` meta tag to the current active span to propagate context to the client
    protected override void OnInitialized()
    {
        var currentTrace = Tracer.CurrentSpan;
        if (!currentTrace.IsRecording)
        {
            _traceParentContext = "00-00-00-00";
        }
        
        var traceId = currentTrace.Context.TraceId;
        var spanId = currentTrace.Context.SpanId;

        _traceParentContext = $"00-{traceId.ToHexString()}-{spanId.ToHexString()}-01";
    }
}

.NET supports OpenTelemetry instrumentation out of the box.

The Highlight.ASPCore NuGet package sets up OpenTelemetry instrumentation and export for highlight, injecting configuration functions for your ASPCore app to simplify instrumentation.

Bootstrap Highlight with your ASP application object.

Update your Program.cs application entrypoint to initialize highlight.

using System.Diagnostics;
using Serilog;

var builder = WebApplication.CreateBuilder(args);
// configure your web application

// create a Serilog logger with Highlight export
Log.Logger = new LoggerConfiguration()
    .Enrich.WithMachineName()
    .Enrich.WithHighlight()
    .Enrich.FromLogContext()
    .WriteTo.Async(async =>
        async.HighlightOpenTelemetry(options =>
        {
            options.ProjectId = "<YOUR_PROJECT_ID>";
            options.ServiceName = "<YOUR_SERVICE_NAME>";
        })
    )
    .CreateLogger();

// Initialize trace, error, metric, and log export
builder.Services
    .AddHighlightInstrumentation(options => options.ProjectId = "<YOUR_PROJECT_ID>");
builder.Logging
    .AddHighlightInstrumentation(options => options.ProjectId = "<YOUR_PROJECT_ID>");

var app = builder.Build();

Verify your errors are being recorded.

Verify that the backend error handling works by triggering the code that reports the error to highlight and visiting the highlight errors portal.

Verify your backend logs are being recorded.

Visit the highlight logs portal and check that backend logs are coming in.

Verify your backend traces are being recorded.

Visit the highlight traces portal and check that backend traces are coming in.

Using highlight.io without a framework in Rust C# .NET 4 ASP