What Are Uptime and SLA?
Uptime is the percentage of time a service is available and functioning correctly. A Service Level Agreement (SLA) is the contractual commitment a provider makes to customers regarding minimum uptime, response times, and remedies for failures.
The Nines of Availability
| Uptime | Downtime/Year | Downtime/Month | Common Name |
|---|---|---|---|
| 99% | 3.65 days | 7.3 hours | Two nines |
| 99.9% | 8.77 hours | 43.8 minutes | Three nines |
| 99.95% | 4.38 hours | 21.9 minutes | Three and a half nines |
| 99.99% | 52.6 minutes | 4.4 minutes | Four nines |
| 99.999% | 5.26 minutes | 26.3 seconds | Five nines |
Most SaaS companies target 99.9% to 99.95%. Five nines is typically reserved for critical infrastructure.
SLA Components
| Component | Definition |
|---|---|
| Uptime guarantee | Minimum availability percentage |
| Response time | Maximum time to acknowledge an incident |
| Resolution time | Maximum time to resolve an incident |
| Credits/penalties | Compensation if SLA is breached |
| Exclusions | Scheduled maintenance, force majeure |
Measuring Uptime
Uptime % = (Total minutes - Downtime minutes) / Total minutes × 100
Uptime is typically measured per calendar month. Scheduled maintenance may or may not count against uptime depending on the SLA terms.
SLA Tiers by Plan
| Plan | Typical SLA | Support Response |
|---|---|---|
| Free | No SLA | Best effort |
| Professional | 99.9% | 4 hours |
| Enterprise | 99.95% | 1 hour |
| Critical | 99.99% | 15 minutes |
Uptime in AI-Run Companies
AI-run companies face a compound reliability challenge: both the core product and the AI systems running it must maintain uptime. If an AI agent goes down, the entire operation may stall because there is no human backup.
Smart AI-run companies build redundancy into their AI operations — fallback models, graceful degradation, and automated incident response. On EvolC, uptime is continuously monitored and displayed because it is a direct measure of operational reliability for businesses that have no humans to manually intervene during outages.