Send Metrics from ASP.NET Core using OpenTelemetry

Instrument your ASP.NET Core application with OpenTelemetry NuGet packages and send HTTP, Kestrel, and .NET runtime metrics to SigNoz.

Most steps are identical. Update the endpoint and remove the ingestion key header as shown in Cloud → Self-Hosted.

Prerequisites

.NET 10 or later
An instance of SigNoz (either Cloud or Self-Hosted)

Send Metrics to SigNoz

Step 1. Add NuGet packages

<ItemGroup>
  <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.15.3" />
  <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.15.2" />
  <PackageReference Include="OpenTelemetry.Instrumentation.Runtime" Version="1.15.1" />
  <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.15.3" />
</ItemGroup>

Or with the .NET CLI:

dotnet add package OpenTelemetry.Extensions.Hosting --version 1.15.3
dotnet add package OpenTelemetry.Instrumentation.AspNetCore --version 1.15.2
dotnet add package OpenTelemetry.Instrumentation.Runtime --version 1.15.1
dotnet add package OpenTelemetry.Exporter.OpenTelemetryProtocol --version 1.15.3

Step 2. Configure OpenTelemetry in Program.cs

using OpenTelemetry.Metrics;
using OpenTelemetry.Resources;
 
var builder = WebApplication.CreateBuilder(args);
 
var serviceName = Environment.GetEnvironmentVariable("OTEL_SERVICE_NAME") ?? "my-aspnetcore-app";
 
builder.Services.AddOpenTelemetry()
    .ConfigureResource(r => r.AddService(serviceName))
    .WithMetrics(m => m
        .AddAspNetCoreInstrumentation()
        .AddRuntimeInstrumentation()
        .AddMeter("Microsoft.AspNetCore.MemoryPool")
        .AddOtlpExporter());
 
var app = builder.Build();
// ... your routes ...
app.Run();

The OTel SDK reads OTEL_EXPORTER_OTLP_ENDPOINT, OTEL_EXPORTER_OTLP_HEADERS, and OTEL_EXPORTER_OTLP_PROTOCOL automatically.

.AddMeter("Microsoft.AspNetCore.MemoryPool") enables aspnetcore.memory_pool.* metrics, which only emit on .NET 10+. On .NET 8 or 9, all other HTTP, Kestrel, and runtime metrics populate as expected. The memory pool panels stay empty.

Step 3. Set environment variables

export OTEL_SERVICE_NAME="my-aspnetcore-app"
export OTEL_EXPORTER_OTLP_ENDPOINT="https://ingest.<region>.signoz.cloud:443"
export OTEL_EXPORTER_OTLP_HEADERS="signoz-ingestion-key=<your-ingestion-key>"
export OTEL_EXPORTER_OTLP_PROTOCOL="http/protobuf"
export OTEL_RESOURCE_ATTRIBUTES="deployment.environment=production"
export OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE="delta"

$env:OTEL_SERVICE_NAME = "my-aspnetcore-app"
$env:OTEL_EXPORTER_OTLP_ENDPOINT = "https://ingest.<region>.signoz.cloud:443"
$env:OTEL_EXPORTER_OTLP_HEADERS = "signoz-ingestion-key=<your-ingestion-key>"
$env:OTEL_EXPORTER_OTLP_PROTOCOL = "http/protobuf"
$env:OTEL_RESOURCE_ATTRIBUTES = "deployment.environment=production"
$env:OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE = "delta"

docker run \
  -e OTEL_SERVICE_NAME="my-aspnetcore-app" \
  -e OTEL_EXPORTER_OTLP_ENDPOINT="https://ingest.<region>.signoz.cloud:443" \
  -e OTEL_EXPORTER_OTLP_HEADERS="signoz-ingestion-key=<your-ingestion-key>" \
  -e OTEL_EXPORTER_OTLP_PROTOCOL="http/protobuf" \
  -e OTEL_RESOURCE_ATTRIBUTES="deployment.environment=production" \
  -e OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE="delta" \
  your-image:latest

env:
  - name: OTEL_SERVICE_NAME
    value: "my-aspnetcore-app"
  - name: OTEL_EXPORTER_OTLP_ENDPOINT
    value: "https://ingest.<region>.signoz.cloud:443"
  - name: OTEL_EXPORTER_OTLP_HEADERS
    value: "signoz-ingestion-key=<your-ingestion-key>"
  - name: OTEL_EXPORTER_OTLP_PROTOCOL
    value: "http/protobuf"
  - name: OTEL_RESOURCE_ATTRIBUTES
    value: "deployment.environment=production"
  - name: OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE
    value: "delta"

Verify these values:

<region>: Your SigNoz Cloud region
<your-ingestion-key>: Your ingestion key
OTEL_RESOURCE_ATTRIBUTES: Sets deployment.environment on all telemetry — the ASP.NET Core Metrics dashboard uses this to filter by environment
OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE: Set to delta to reduce metric costs. See Use Delta Temporality.

OpenTelemetry SDKs export metrics with cumulative temporality by default, which re-sends the running total of every active series on each export interval — even when nothing has changed. With OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE set to delta, synchronous instruments (like Counters and Histograms) that record nothing during an export interval send no data points for that interval, reducing the number of billable samples.

Observable (asynchronous) instruments emit a data point on every collection cycle regardless of temporality. See Use Delta Temporality for details.

Step 4. Validate

Start your application, send some requests, then open SigNoz.

Go to Metrics > Metrics Explorer.
Search for http.server.request.duration.

Metrics appear within the first export interval (default: 60 seconds).

Troubleshooting

Still not seeing data in SigNoz? Work through Debug missing traces, logs, and metrics, which covers SDK diagnostics, Collector connectivity, and the common ingestion errors for all three signals.

Metrics not appearing

Check that OTEL_EXPORTER_OTLP_ENDPOINT is reachable from your application host. Look for OpenTelemetry startup messages in the application logs — the SDK logs the endpoint and exporter configuration at startup.

Metrics delayed

The default export interval is 60 seconds. Reduce it for faster feedback during development:

OTEL_METRIC_EXPORT_INTERVAL=10000

Authentication errors

Verify the header is exactly signoz-ingestion-key=<your-key> with no extra spaces or quotes.

Metric `aspnetcore.memory_pool.*` not appearing

These metrics require .NET 10+ and only emit when Kestrel reads request bodies. Add POST endpoints that read req.Body to trigger them.

Next steps

ASP.NET Core Metrics dashboard — import the pre-built dashboard for this setup
Set up alerts on your metrics
Send traces from your .NET application