SLI

SRE / DevOps concept Service Level Indicator.

Definition

A SLI (Service Level Indicator) is a raw metric measuring a service quality dimension: request success rate, p99 latency, availability, throughput. Good SLIs are side-effect-free and user-facing — expressed as percent of success / window. EDI example: percentage of INVOICs mapped correctly per hour.

Origin

Concept popularised by the Google SRE Book (2016). Chapter 4 — Service Level Objectives.

Example in context

EDI SLI: count(success_invoices_total) / count(total_invoices_received) on 30-day rolling window.

Related terms

• SLO — objective based on SLI.