One thing we've been thinking about while building monitoring systems:

A website returning HTTP 200 doesn't necessarily mean it's working.

You can have:

• a homepage returning 200 while login is broken
• an API returning 200 with an invalid response
• checkout failing halfway through
• SSL working today but expiring tomorrow
• DNS working from one location but failing somewhere else
• a background job silently stopped
• a critical browser flow broken while the page itself loads perfectly

So what should an uptime monitor actually consider a healthy service?

Is HTTP + response time enough for you, or do you expect monitoring to understand the application itself?

Curious how others approach this – especially for production SaaS and e-commerce.