DevOps Dictionary

Service Level Indicator (SLI) is a quantified measure of a service behavior that users actually experience, such as availability (successful requests), latency (response time), error rate, or data freshness. It turns ambiguous reliability questions into a number computed from telemetry like metrics, logs, or traces over a defined scope and time window, for example the percentage of requests that succeed over the last 30 days or the share of jobs that complete within a threshold. With a Service Level Indicator (SLI), teams can set clear objectives, detect regressions early, and make priority tradeoffs based on measured user impact, while without it reliability debates become subjective, alerting becomes noisy, and outages are harder to explain and prevent. This gap exists because raw operational signals are high volume and uneven, and an SLI intentionally aggregates them into a decision ready view.