Backend & systems·Observability and operations
you promise the customer 99.5 percent in a contract with money attached if you miss it.
Service level agreement
Also calledSLA
An externally committed reliability target with consequences, usually financial. It should be strictly looser than your internal SLO, so that you are alerted and acting long before a contractual breach. Engineers rarely need to set one; they very often need to know it is not the same thing as the SLO.