An SLA is the promise you make to customers about reliability, and it is a business contract, not just an engineering target.
An SLA (Service Level Agreement) is a formal commitment between a service provider and its customers about the level of service to be delivered, usually availability or performance, often with defined consequences such as service credits if the target is not met.
These three terms are related but distinct. An SLI (Service Level Indicator) is the measured quantity, for example the percentage of successful requests. An SLO (Service Level Objective) is the internal target set on that indicator, say 99.9% over 30 days. An SLA is the external, contractual promise, often set looser than the SLO, with commercial consequences if it is breached. The relationship matters: you manage internally to the tighter SLO, which leaves a safety margin so you rarely breach the looser SLA you promised customers.
An SLA is as much a commercial and legal document as a technical one. It specifies the metric and target (for example, 99.9% monthly uptime), how and over what window it is measured, exclusions such as scheduled maintenance, the remedies if it is missed (typically service credits or penalties), and how compliance is reported. Because breaching it has real financial and reputational consequences, an SLA is negotiated carefully and set at a level the provider is confident of meeting.
The practical division of labour is that the SLO drives engineering decisions and the SLA drives the customer relationship. Teams track SLOs internally and use error budgets to decide when to slow down and stabilise, precisely so that the external SLA is never at risk. When an organisation confuses the two, promising customers the same number it targets internally, it leaves no margin, and the first bad month becomes a contractual breach. The gap between the SLO and the SLA is the buffer that protects the promise.
Ops Singularity helps protect SLAs by keeping SLOs healthy: it computes SLIs from request-level telemetry and prioritises autonomous resolution where an error budget is burning fastest, so the internal target that protects your external promise stays on track.
An SLO is an internal reliability target; an SLA is an external contract with customers, often set looser than the SLO and carrying financial consequences if breached.
The provider typically owes the remedy defined in the contract, usually service credits or penalties, plus the reputational cost. This is why SLAs are set at levels providers are confident of meeting.
To leave a safety margin. Managing internally to a tighter SLO means a bad period is unlikely to breach the looser SLA promised to customers.
Ops Singularity turns open telemetry into autonomous, governed resolution. See it on your own stack.