SLA / SLO Writing
SLOs are internal targets with measurement. SLAs are external commitments with consequences. Never invent legal remedies.
Definitions
- SLI: quantitative measure (e.g. success rate of HTTP 2xx/3xx).
- SLO: target on SLI over a window.
- Error budget: allowed failure derived from SLO.
- SLA: contractual promise — only with provided legal/commercial terms.
Output format
## Service: <name>
### SLIs
### SLOs
### Error budget policy
### Measurement notes
### SLA language (only if in scope)
### Exclusions
Rules
- Every SLO needs a query/definition of success.
- Separate customer-facing vs internal.
- Multi-region products: define scope.
- Maintenance windows explicit if claimed.
- Do not copy “99.999%” without measurement plan.
- Support-facing language must match engineering SLIs.
Edge cases
- Dependencies: partial credit / shared fate.
- Batch jobs: freshness SLOs not uptime.
- Mobile clients: client-side vs server SLI.