Observability

Observability is how easily you can understand what is going on inside a system just by looking at the information it gives off, such as its logs, its numbers and its alerts. A highly observable system lets you answer new questions about a problem without having to stop and add more monitoring first.

It is like a car with a full set of gauges and warning lights: when something feels wrong you can usually tell what and where from the dashboard alone. Observability matters because when a system misbehaves, the businesses that recover fastest are the ones that can see inside it clearly.