Observability
Also written as Monitoring, Datadog
The practice of instrumenting systems (logs, metrics, traces) so engineers can understand what's happening inside them and diagnose problems in production.
Think of it like
Like a car's dashboard gauges and a black-box flight recorder combined — you can see what's happening right now and reconstruct exactly what happened after something goes wrong.
Junior or senior?
Junior sounds like
Reacts to outages as they happen with no proactive monitoring.
Senior sounds like
Has set up dashboards and alerts proactively, and can describe an incident they diagnosed using logs, metrics, or traces.
Ask them
“Tell me about a production incident you diagnosed using logs, metrics, or traces.”
Sounds like real experience
Walks through a real incident — what the dashboard or trace actually showed, and the specific signal that led them to the root cause — not just that monitoring exists.
Probe further if
Says they 'have monitoring' or name a tool without describing a specific incident where logs, metrics, or traces actually led them to a root cause.