Observability is more than collecting logs. It is the ability to understand what your production system is doing and answer new questions without deploying new code. Logs, metrics, and traces work together to help you identify and resolve issues quickly.
This article covers the practical foundations that every modern .NET service should have.
Structured logs over print statements
Console.WriteLine() is useful during development, but it quickly becomes insufficient in production.
Instead, emit structured logs with consistent fields so they can be filtered and queried efficiently.
Useful fields include:
- RequestId
- TraceId
- UserId
- Endpoint
- Duration
- StatusCode
Libraries such as Serilog, Microsoft.Extensions.Logging, and OpenTelemetry Logging make it easy to send structured logs to platforms like Elasticsearch, Loki, or Seq.
Measure the metrics that matter
Don’t try to monitor everything. Focus on the metrics that directly reflect user experience.
Common examples include:
- Error Rate
- Requests Per Second (RPS)
- p95 / p99 Latency
- CPU and Memory Usage
- Queue Length
- Active Connections
Alerts should be based on user-facing symptoms rather than every internal fluctuation.
Use tracing to follow a request end to end
Modern applications often consist of multiple services.
A single request may travel through an API Gateway, Authentication Service, Payment Service, Notification Service, and finally the database.
By propagating a TraceId across every service, you can follow the complete request lifecycle instead of trying to correlate disconnected log entries.
With OpenTelemetry, distributed tracing is straightforward to implement in .NET applications and integrates well with Jaeger, Grafana Tempo, and Zipkin.
Conclusion
Observability starts with good engineering practices, not expensive tools. Structured logging, meaningful metrics, and distributed tracing provide the visibility required to operate production systems with confidence.
The sooner you can understand what’s happening inside your system, the faster you can solve problems before your users notice them.