Service level objectives (SLOs)
| SLI | Objective | Measurement |
|---|---|---|
| API availability (paid tiers) | 99.9 % monthly | Uptime check on the API health endpoint + ratio of non-5xx responses |
| API availability (free tier) | 99.5 % monthly | Same |
| API latency | p95 < 400 ms | Cloud Monitoring request latency (Cloud Functions / Run) |
| PDF generation | p95 < 6 s warm; queue age < 2 min | Outbox job age metric |
| Clinical editor render | < 200 ms for 200 fields | Frontend performance budget (CI) |
| LIS worklist (R2) | p95 < 500 ms at 20 users & 10k samples/day | Load test gate |
Error budget: 0.1 % of monthly minutes (≈ 43 min) for 99.9 %. Burning more than 50 % of the monthly budget in a week freezes non-urgent releases until reviewed.
Alert policies (5xx rate, latency) and the uptime check are defined in Terraform
(infra/modules/monitoring).