Service Level Indicators
Service Level Indicators (SLIs) are quantitative measures of a service's performance, reliability, or availability, such as latency, error rate, or throughput. They are used to define and monitor the quality of service from a user's perspective, providing objective data to assess whether a service meets its intended goals. SLIs are a core component of Service Level Objectives (SLOs) and Service Level Agreements (SLAs) in site reliability engineering and DevOps practices.
Developers should learn and use SLIs to ensure their services are reliable and meet user expectations, particularly in cloud-native or distributed systems where failures can impact business outcomes. They are essential for setting measurable performance targets, automating monitoring and alerting, and making data-driven decisions about resource allocation and feature development, such as prioritizing bug fixes over new features when error rates exceed thresholds.