What is the difference between monitoring and observability?

Monitoring and observability are related but distinct concepts. Monitoring is the practice of collecting predefined metrics, logs, and alerts to track whether a system is behaving as expected. You decide upfront what to watch — CPU usage, request rate, error count — and dashboards or alerts fire when thresholds are breached. It answers the question: Is something wrong?

Observability goes further. A system is observable if you can understand its internal state purely from its external outputs — metrics, logs, and traces — without deploying new instrumentation every time a new failure mode appears. It answers: Why is something wrong? The term originates from control theory: a system is observable if its internal states can be inferred from its inputs and outputs.

In practice, monitoring is a subset of observability. You can have monitoring without observability (dashboards that tell you something is broken but not why), but you cannot have genuine observability without a solid monitoring foundation. High-cardinality telemetry, distributed tracing, and structured logging are the tools that push a system from merely monitored to truly observable.