Uptime monitoring vs health checks: why you need both

Uptime monitoring pings a URL and checks for a 200 response. If the server is running, the check passes. But a SaaS product can be "up" while being completely broken: the server returns 200 but Stripe webhooks are failing silently, the database connection pool is exhausted, the auth provider is rate-limiting your requests, and email delivery is bouncing. Your uptime monitor shows green while customers cannot sign up, pay, or receive notifications.

What uptime monitoring misses

Traditional uptime monitoring checks: is the process running? Is the port responding? Does the homepage load? It does not check: can users authenticate? Does the payment flow complete? Are webhooks being delivered? Is the database accepting writes? Are background jobs processing? These are the failures that actually impact customers.

Deep health checks verify behavior

A health check should verify system behavior, not just system availability. Can the database accept a query? Can the payment provider respond to an API call? Does the auth endpoint return valid session information? Does the email provider accept a send request? These probes test the critical path, not just the infrastructure layer.

Provider SLA tracking

Your SaaS depends on third-party providers: Stripe, Supabase, Resend, Twilio, Clerk. Each has its own reliability profile. Tracking seven-day pass rate, average latency, and failure count per provider reveals which integrations are flaky and which are solid. This data helps you decide where to add fallbacks, retries, or provider switches.

Why you need both layers

Uptime monitoring catches catastrophic failures: server crash, DNS misconfiguration, certificate expiry. Health checks catch operational failures: payment drift, auth breaks, provider degradation. Running only uptime monitoring is like checking that a restaurant is open without checking if the kitchen has ingredients. PreFlight provides the deep health layer that uptime monitoring tools skip.