# Uptime monitoring

> An outside service pinging your site every minute and alerting when it stops answering — so you hear about the outage before your customers do.

The check that matters is from outside: a monitor on the same server reports 'all good' right up until the server dies. External probes — HTTP 200 with the right content, not just a ping — catch the real failures: expired certificates, dead app servers, a deploy that returns the maintenance page.

The honest target setting matters more than the tool: four nines (99.99%) is fifty-two minutes of downtime a year; three is eight hours. Monitoring with no on-call answer is a log of when you were down, not protection — the alert has to reach someone who can act.

## Related terms

- https://dfieldsolutions.com/en/glossary/incident-response.md
- https://dfieldsolutions.com/en/glossary/http-caching.md
- https://dfieldsolutions.com/en/glossary/ci-cd.md

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Source: https://dfieldsolutions.com/en/glossary/uptime-monitoring
DField Solutions — Dunakeszi, Hungary — dezso@dfieldsolutions.com
Booking: see https://dfieldsolutions.com/en/contact