SLI

Service Level Indicator

Actual measured metric (latency, error rate) backing the SLO.

When you'd see it: Reliability and SRE practice, alongside SLO and SLA. The SLI is the actual measured number.

Why it matters: An SLI is the concrete metric (request latency, error rate, uptime) you measure to know whether you are meeting your SLO. Without good SLIs, reliability targets are just words.

Common mistakes: Picking SLIs that are easy to measure rather than ones users feel. The right SLI tracks the experience, not just what the dashboard happens to show.