Every check runsfrom every region

One location only gives you one view of the internet. A network blip or routing issue near that location looks exactly like your site going down. Checking from fifteen regions shows you which it is, and an outage has to be confirmed across regions before anyone is alerted.

Fifteen: Ashburn, Chicago, Seattle, Toronto, Mexico City, São Paulo, London, Frankfurt, Tel Aviv, Johannesburg, Mumbai, Singapore, Tokyo, Seoul and Sydney. Every check runs from all fifteen, which is the number that matters. Many monitoring services list a dozen locations and check from one of them at a time.

No. Sentinel doesn't rotate scheduled checks between regions. Every scheduled check runs from all fifteen regions, so on a 30-second interval every region checks your site every 30 seconds. The regions are spread out within each interval, so your server never gets fifteen requests at the same instant, but no region ever skips a turn.

No. All fifteen regions take part in normal scheduled monitoring, not just in confirming a failure. Consensus decides whether a failure becomes an outage alert, but every region reports on every check either way.

A monitor is marked down only when at least half of its regions agree it's unreachable, and at least three of them are on two different continents. With all fifteen regions on, eight have to agree. A transient issue in one region stays visible on the monitor but won't wake your on-call team.

SentinelBot is a verified bot in Cloudflare's Radar directory, so checks from all fifteen regions are recognized as legitimate monitoring traffic on Cloudflare-protected sites instead of being challenged. The user agent is documented and Sentinel's monitoring IPs are published for allowlisting on other firewalls.

You can see it. Because every check runs from fifteen regions, the monitor view shows each region's latest result side by side, so a site that's down in Europe but up in North America looks exactly like that. Alerts are reserved for outages the regions confirm together, so a blip visible from only one region won't page you. If a specific region matters enough to alert on, such as the market your customers are in, add a second monitor scoped to just that region and it will alert on that region alone.

The check interval depends on your plan, from every 5 minutes on the free plan to every 15 seconds on Business. Whatever the interval, every region checks at it. More frequent checks mean faster detection and faster confirmation of real outages.

Once an outage is verified across regions, Sentinel sends alerts by email, SMS, Slack, Discord, Telegram, or webhook and opens an incident with an automatic timeline of which regions were affected.