Introduction
SLOs (Service Level Objectives) and SLIs (Service Level Indicators) form the foundation of Site Reliability Engineering (SRE). In 2026, mature organizations go beyond monitoring technical metrics: they align reliability with actual user expectations. Effective SLO management enables informed decisions on product priorities, infrastructure investments, and risk-versus-velocity trade-offs. This tutorial provides a structured method to move from reactive monitoring to proactive reliability governance.
Prerequisites
- Basic knowledge of monitoring and observability
- Familiarity with availability and latency concepts
- Experience managing digital services or products
- Access to existing metrics data (even partial)
Step 1: Identify Critical User Journeys
Start by mapping the journeys with the highest business impact. For an e-commerce site, this might include adding items to the cart and completing checkout. For a SaaS application, it often involves login and report generation. Use the following matrix to prioritize:
| User Journey | Frequency | Business Impact | Criticality |
|---|---|---|---|
| -------------- | ----------- | ------------------ | ------------- |
| Login | Daily | High | Critical |
| Data Export | Weekly | Medium | Important |
Step 2: Define Relevant SLIs
An SLI is a quantitative measure of service performance from the user's perspective. The four classic categories are availability, latency, throughput, and errors. For each critical journey, select a maximum of 2-3 SLIs. Concrete example: for a payment service, the SLIs could be the rate of successful requests (availability) and the 95th percentile latency of confirmation.
Step 3: Set Realistic and Measurable SLOs
An SLO is the target objective for an SLI over a given period. The golden rule: start conservative, then tighten. Example: "99.5% of payments must succeed over a rolling 28-day window". Systematically document the window, threshold, and measurement method. Avoid overly ambitious SLOs that generate constant alerts and team fatigue.
Step 4: Implement Tracking and Alerts
Build an SLO dashboard that includes error budget burn rate. Configure alerts based on remaining error budget rather than absolute thresholds. Example policy: yellow alert at 50% budget consumed, red alert at 80%. This provides time to react before the SLO is breached.
Step 5: Conduct SLO Reviews and Trade-offs
Hold monthly reviews with product and technical stakeholders. Use this framework: if the error budget is being consumed too quickly, discuss options (improve reliability, reduce scope, or temporarily accept a lower SLO). Document every decision in a trade-off register.
Best Practices
- Limit to 3-5 SLOs per service to stay actionable
- Always measure from the end-user perspective (client-side)
- Conduct quarterly SLO reviews with product teams
- Systematically document trade-offs and their rationale
- Use SLOs to prioritize technical investments
Common Mistakes to Avoid
- Defining SLOs on technical metrics with no link to user experience
- Setting overly ambitious targets from the start (e.g., 99.99% without justification)
- Forgetting to measure burn rate and react in time
- Ignoring SLOs during product roadmap reviews
Going Further
Deepen these concepts with our comprehensive training on reliability engineering. Discover our Learni trainings.