Observability

How trace sampling affects production debugging: head, parent-based, and tail sampling trade-offs, error traces, rare paths, and async work.

How correlation IDs in microservices connect logs, traces, queues, and background jobs across service boundaries without replacing tracing or metrics.

Observability vs logging in production, with a practical guide to when logs, metrics, traces, and correlation IDs answer different debugging questions.

A practical OpenTelemetry guide for backend engineers: what to instrument first, and how traces, metrics, logs, sampling, and collectors aid debugging.