Glossary term
What is SLO (Service Level Objective)?
SLO stands for Service Level Objective.
In DevOps
A reliability target for a measurement (SLI), such as 99.9% of requests succeed. The gap to 100% is the error budget.
Learn it properly · DevOpsLesson 17: Monitoring and Logging with CloudWatchKnowing what your system is doing before your users tell you: metrics, logs, alarms and dashboards.In System Design
Your target for an SLI. Example: 99.9% of checkouts succeed over 28 days.
Learn it properly · System DesignLesson 47: SLI, SLO, SLA & Error BudgetsProduct wants to ship daily; operations wants fewer changes; nobody agrees what “reliable enough” means. SLIs, SLOs and SLAs turn it into one number, and error budgets turn that number into a simple rule for when to move fast and when to slow down.In Full-Stack Questions
A target for how reliable a service should be, such as 99.9% of requests succeed.
Learn it properly · Full-Stack QuestionsLesson 26: Deployment, CI/CD and MonitoringVercel deploys, Docker for Node, GitHub Actions, feature flags, safe rollouts and migrations, Sentry, OpenTelemetry and SLOs.In Team Lead Mindset
A target for how well a service should work, such as '99.9% of requests succeed'. An SLI is the measure it uses.
Learn it properly · Team Lead MindsetLesson 6: Technical Debt, Quality and the Rewrite TrapDebt as a loan with interest, refactor or rewrite, a test plan, what to monitor, and lessons from five famous public outages.In Observability & SRE
A target for an SLI over a time window, such as 99.9 percent of requests succeed over 30 days.
Learn it properly · Observability & SRELesson 4: SLIs, SLOs and Error BudgetsChoosing indicators, setting objectives, how nines translate to minutes, burn rates and what error budgets are for.