Install the ErrTap NuGet package for ASP.NET Core — middleware for unhandled exceptions plus manual capture and structured logs. Includes a snippet for classic ASP.NET Framework.

Install

dotnet add package ErrTap

Until the package is published to NuGet, reference the project from the monorepo:

<ProjectReference Include="path/to/sdk/sdk-dotnet/ErrTap.csproj" />

ASP.NET Core setup

// Program.cs
using ErrTap;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddErrTap(o =>
{
    o.Dsn = builder.Configuration["ErrTap:Dsn"]!; // https://et_…@api.errtap.com
    o.Environment = builder.Environment.EnvironmentName;
});

var app = builder.Build();
app.UseErrTap(); // report unhandled exceptions, then rethrow
app.Run();

// appsettings.json
{
  "ErrTap": {
    "Dsn": "https://et_your_key@api.errtap.com"
  }
}

UseErrTap() adds middleware that reports any unhandled exception and rethrows it, so your existing error pages and logging keep working.

Manual capture & logs

The static ErrTap class is available anywhere after setup:

try { /* … */ }
catch (Exception ex)
{
    ErrTap.CaptureException(ex);
    throw;
}

ErrTap.Info("checkout started", new Dictionary<string, object?> { ["orderId"] = id });
// also: ErrTap.Debug / ErrTap.Warning / ErrTap.Error / ErrTap.CaptureMessage

Options

Field	Type	Description
`Dsn`	`string`	URL DSN (`https://et_…@host`) or bare key (requires `Endpoint`)
`Endpoint`	`string?`	Override for `/ingest/error`; required when `Dsn` is a bare key
`Environment`	`string`	Defaults to `production`
`Release`	`string?`	Ties errors to a deploy
`Tags`	`IDictionary<string, object?>?`	Attached to every event

Classic ASP.NET (Framework)

There's no NuGet package for System.Web — post directly to the ingest API from Application_Error:

// Global.asax.cs — Application_Error (.NET Framework / System.Web)
using System;
using System.Net.Http;
using System.Text;
using System.Web;
using System.Web.Script.Serialization;

protected void Application_Error(object sender, EventArgs e)
{
    var ex = Server.GetLastError()?.GetBaseException();
    if (ex == null) return;

    var json = new JavaScriptSerializer().Serialize(new
    {
        message = ex.Message,
        type = ex.GetType().FullName,
        stacktrace = ex.ToString(),
        environment = "production",
    });

    using (var client = new HttpClient())
    using (var req = new HttpRequestMessage(HttpMethod.Post, "https://your-host/ingest/error"))
    {
        req.Headers.TryAddWithoutValidation("Authorization", "DSN et_<your-key>");
        req.Content = new StringContent(json, Encoding.UTF8, "application/json");
        client.SendAsync(req); // fire-and-forget; never block the error page
    }
}

See the Ingest API reference for the full payload shape.

.NET SDK

Install

ASP.NET Core setup

Manual capture & logs

Options

Classic ASP.NET (Framework)

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