SLO, SLA, SLI
A service level indicator (SLI) is a measurement of service behavior, such as the share of requests that succeed. A service level objective (SLO) is a target for an SLI over a window, such as 99.9% over 30 days. A service level agreement (SLA) is a contract with customers that sets consequences, such as service credits, when a promised level is missed; it is usually looser than the internal SLO.
Reliability
In Quorum#
The SLI is availability: the share of user requests answered over the last calendar week, without bots and WAF blocks. Each Era sets the SLO, from 99% in Garage to 99.99% in Public, and from Series A the failures it allows are your error budget. SLO dashboards put that budget on the HUD, and the IPO checklist needs 99.95%. The game has no SLA yet.