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WebPixie

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Why Cloudflare Can Make Your Uptime Monitor Lie to You

A “website down” alert does not always mean your server is actually down.

If your site is behind Cloudflare, your monitoring request can fail because:

  • Cloudflare blocks the monitoring bot
  • A WAF rule returns 403
  • Rate limiting returns 429
  • Cloudflare itself is experiencing an outage

Meanwhile, your origin server may still be perfectly healthy.

One useful signal is the cf-mitigated response header. If it is present, Cloudflare intervened before the request reached your server.

The more reliable approach is to distinguish between:

  1. Cloudflare blocking the monitor
  2. Cloudflare having an outage
  3. Your origin actually being down

We broke down how to diagnose each case — and three ways to reduce false downtime alerts:

👉 https://webpixie.io/blog/post/cloudflare-false-downtime-alerts

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