Locations and checks
Spectate runs uptime checks from checkers in four regions. Each monitor has one primary region, and every check of the monitor runs there. Before Spectate marks a monitor down, a second check from the same region, about 5 seconds later, must confirm the failure.
Regions
| Region | primary_location in the API |
|---|---|
| Europe | eu |
| North America | us |
| Asia | as |
| Oceania | oc |
The checks of a region come from its own IP addresses. IP addresses has the current list, also as plain text for firewalls.
To change the region of a monitor, open the monitor and select the Settings tab. Under Region, select the region, then select Save changes. Uptime, response times, charts and alerts of the monitor all come from this region. Select the region that is nearest to your users, or nearest to the server, to measure without long network paths.
How often Spectate checks
A checker asks Spectate for the monitors that are due, about every 10 seconds. A monitor is due when its Interval has passed since its last check. One checker in the region gets the monitor, so each check runs one time.
Two kinds of monitors do not wait for the interval:
- Spectate checks a new monitor as soon as a checker asks.
- Spectate checks a monitor that is down every time a checker asks, until it is up again. So Spectate sees a recovery soon after it happens.
The plan sets the shortest interval: 60 seconds on Starter, 30 seconds on Team and Business. See Uptime monitors.
How Spectate confirms a failure
- A check fails, for example with a timeout or an unexpected status code.
- The checker waits about 5 seconds.
- The checker runs the check again, from the same region. This is the recheck.
- If the recheck succeeds, the monitor is up. Spectate fires no alert.
- If the recheck also fails, the monitor is down. Spectate fires the alert "NAME is down" with the severity
critical.
The recheck does not run from another region. The other regions never change the uptime or the alerts of a monitor. With Also measure response time from the other regions (Team and Business plans), they only measure its response time for comparison.
For HTTP and HTTPS monitors, the recheck that makes the monitor down also records a failure snapshot. One successful check makes the monitor up again, and Spectate resolves the down alert at once.
While the alert fires, Spectate does not fire a second down alert for the same monitor. The escalation path of the alert decides who gets notified, and when.
Recognise the checks
HTTP and HTTPS checks send this User-Agent header, unless the monitor sets its own:
Code
If a firewall, a WAF or a bot filter blocks the checks, allow the user agent or the IP address of the monitor's region. See The uptime monitor bot and IP addresses.
Each HTTP check opens a new connection. It does not keep cookies between checks. The check measures DNS lookup, connection, TLS handshake and time to first byte. The Heartbeats tab shows these times per check in Check log · 24h.
Targets Spectate does not check
Spectate checks only public addresses. It refuses targets that are, or resolve to, private, loopback, link-local, carrier-grade NAT, multicast or reserved addresses. Examples are 10.0.0.5, 192.168.1.1, 127.0.0.1 and 169.254.169.254. The checker tests the address again before each connection, also after a redirect.
To monitor a server on a private network, give it a public address or a public URL. For metrics from inside the network, install the Spectate host agent.