intermediate

Tools

Common observability products and open-source tools used for dashboards, metrics, logs, traces, errors, and application monitoring.

Tool interviews map products to problems: Grafana for dashboards, Prometheus for metrics, Loki for label-indexed logs, Datadog/New Relic for hosted APM, Sentry for errors and frontend releases—not "we bought X so we are observable."

Subtopics: Grafana, Prometheus, Loki, Datadog, Sentry, New Relic.

On interviews: choose a stack for a 10-person JS team; when Sentry complements Prometheus; OTel export to multiple backends.

Common pitfalls: tool sprawl without standards; duplicate agents; expecting vendor to define SLIs for you.

The trade-off is integrated SaaS convenience versus cost, portability, and operational ownership.

Checklist:

Match tool to signal type.
Standardize tags/labels across tools.
Prefer OTel where possible.
Review vendor cost drivers monthly.