StatusCake monitors uptime, SSL expiration, and DNS — the basic 'is the site reachable' layer. StoreVitals monitors what's happening on the pages themselves — SEO, accessibility, security headers, broken links. The 'is it up' check vs. the 'is it healthy' check.
StatusCake answers 'is the site up?' StoreVitals answers 'is the site healthy?' A store that's 100% uptime can still be hemorrhaging traffic to a noindex tag added during a redesign, a Core Web Vitals failure from a third-party app install, or a structured data error that killed rich snippets. Most ecommerce teams need both: StatusCake for downtime alerts, StoreVitals for the broader health signals that don't trigger downtime but suppress revenue.