What are SLO, SLA, and SLI? Simple Explanation with Examples

What are SLO, SLA, and SLI? If you’ve ever dived into SRE (Site Reliability Engineering) or service monitoring, you’ve likely seen three mysterious abbreviations: SLO, SLA, and SLI. They might look similar, but they play different roles in how we measure and guarantee reliability. SLI — Service Level Indicator This is a metric that tells you how your service is doing. Examples: Latency (e.g., “response time of API requests”) Availability (e.g., “percentage of successful requests”) Error rate (e.g., “number of 5xx responses”) 👉 Think of SLI as a thermometer — it measures the state of your system. ...

September 25, 2025 · 2 min · 297 words · John Cena