Service
Website uptime monitoring
We request each monitored URL (by default every 10 seconds) and record the HTTP status code and response time.
What the statuses mean
- Up
- The URL returned an expected status code (by default 200–399). You can set your own expected codes, such as
200or200,301. - Access restricted
- The server answered with HTTP 401 or 403. The endpoint is reachable but requires credentials or blocks monitors. This is not treated as an outage.
- Down
- DNS failure, connection refused, timeout, TLS handshake failure, or an unexpected HTTP status.
- Stale
- No recent measurement is available. We never present missing data as downtime.
Certificates do not decide availability
The availability probe reads the HTTP response even if the certificate is expired, self-signed or issued for another name. That problem is reported separately under SSL status, so a working site with a certificate warning shows Up plus an SSL invalid warning.
Redirects
By default a redirect (3xx) response counts as Up and the destination is shown but not requested. You can enable redirect following per website; each destination is validated before it is contacted, up to five hops.
Incidents and alerts
An incident opens only after a configurable number of consecutive failed checks (default 3), which filters out one-off network blips. You receive one outage alert and one recovery alert per incident, never duplicates.
Fair use and safety
Only public websites on standard ports (80 and 443) can be monitored. You verify ownership of each domain with a DNS TXT record or a small file. Private, internal and cloud-metadata addresses are always blocked.