Correlation IDs in ASP.NET Core --- Designing Observability Like a Senior Engineer (2026 Edition)

Correlation IDs in ASP.NET Core --- Designing Observability Like a Senior Engineer (2026 Edition) Cristian Sifuentes \ Senior .NET Engineer · Distributed Systems & Observability TL;DR If your system spans multiple services and you don't have Correlation IDs, you are debugging blind. A Correlation ID is not a logging trick.\ It is a traceability contract between services. In this deep dive we will: Implement production-grade Correlation ID middleware Attach it correctly to logging scopes Propagate it across HttpClient boundaries Compare it with Idempotency Keys (correctly) Align it with modern distributed tracing principles Discuss pitfalls most developers don't notice This is not a beginner guide. This is how senior engineers design debuggable systems. The Real Problem: Debugging Distributed Systems In 2026, very few systems are monoliths. Your architecture probably looks like this: Client → API Gateway → Order Service → Payment Service → Notification Service Each component writes logs