Why Observability and DX Matter
System design isn’t only about scaling and consistency—it’s also about observability (knowing what’s happening in production) and developer experience (how quickly and safely you can ship). This section covers logging and metrics, alerting, and the practices that make development and deployment smooth.
Observability: logging and metrics
Performance monitoring (e.g. DataDog)
Tools like DataDog (and alternatives such as New Relic, Prometheus + Grafana) give you performance monitoring and business insights. You get a view of system health: latency (e.g. P99), error rates, throughput, and resource usage. That helps you spot regressions, capacity issues, and bottlenecks. Dashboards and alerts turn raw metrics into something you can act on.