Incident timeline - checkout service outage

14:02 - Alert fired (checkout API error rate above 5%)
14:06 - On-call engineer acknowledges
14:14 - Root cause suspected (13:55 config change to payment gateway)
14:20 - Rollback initiated
14:31 - Rollback completed, error rate dropping
14:38 - Error rate back to baseline
14:40 - Incident declared resolved

Total downtime (alert to resolution): 38 minutes.

Postmortem summary: A config change deployed at 13:55 to the payment gateway
caused checkout error rates to exceed 5% by 14:02. On-call rolled back the
change by 14:31, and the incident was declared resolved at 14:40 once error
rates returned to baseline, for a total of 38 minutes of impact.