SLA
Service Level Agreement: a contractual commitment between provider and customer specifying uptime, response time, and penalties for breaches. The business version of an SLO.
What is SLA?
Service Level Agreement: a contractual commitment between provider and customer specifying uptime, response time, and penalties for breaches. The business version of an SLO.
SLA is a advanced concept that sits in the Reliability & Resilience area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "SLA" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
Learn SLA in depth
Full interactive lesson with diagrams, code examples, real-world references, and a quiz.
Open the SLA lessonRelated lessons
Lessons that touch on SLA as part of a larger topic.
SLA (Service Level Agreements)
The legally binding reliability promise, when missing your targets has financial consequences
intermediate · observability monitoring
SLA/SLO/SLI Overview
Putting it all together, how SLIs, SLOs, and SLAs work as a unified reliability framework
intermediate · observability monitoring
Performance Testing
Measuring and optimizing response times, throughput, and resource usage to meet performance SLAs
intermediate · devops cicd
Availability Metrics
Measuring how reliably your system serves requests, the nines that define your reputation
intermediate · observability monitoring
Slack Notifications
Real-time team alerts in Slack channels. ChatOps integration for incident response
advanced · reliability resilience
See also
Related glossary terms you might want to look up next.
SLO
Service Level Objective: a target value for an SLI, like '99.9% of requests under 300ms.' The internal engineering goal that drives reliability investment.
SLI
Service Level Indicator: a quantitative measure of service behavior, like the proportion of requests faster than 300ms. The raw metric that feeds SLOs.
Availability
The percentage of time a system is operational and accessible. Measured in 'nines' — 99.99% availability means about 52 minutes of downtime per year.