This page may contain stale information. Last updated: 2026-06-12
Definition
Service availability refers to the percentage of time a service is operational and accessible to users. Measured in “nines” (99%, 99.9%, 99.99% etc.).
Key Points
- SLA (Service Level Agreement) targets
- Causes of downtime (maintenance, failures, incidents)
- High-availability architecture patterns
- Monitoring and alerting
- Model retirement: API requests to retired AI models fail immediately — zero availability after cutoff (2026-06-12-anthropic-claude-api-june-15-deprecation)