How is website deployment success measured (uptime, speed, rollback readiness)?

Deployment success is measured across three dimensions: availability, performance, and recoverability. Availability is tracked through uptime percentage (target 99.9% or higher for business-critical sites, equivalent to less than 8.7 hours of downtime per year) measured by external monitoring services that test from multiple geographic locations. Error rate (HTTP 5xx responses as a percentage of total requests) provides a more granular view of application-level failures that uptime monitoring may not capture.

Performance post-deployment is measured by comparing Core Web Vitals scores, TTFB, and page load times against the pre-deployment baseline using tools like SpeedCurve or Calibre for continuous performance tracking. Rollback readiness is measured by mean time to rollback (MTTR): how quickly the team can revert a bad deployment to the previous stable version. A deployment process without a tested rollback procedure is incomplete; rollback capability should be validated in a staging environment before it is needed in a production emergency.