SentrynelKnow about downtime before your customers do
Checks every minute from independent probe nodes. Every outage is confirmed by a second opinion before we wake you up - no false alarms.
No credit card · up to 50 monitors free · Czech & English
1 min
between checks
7+SSL
monitor types
2+
nodes confirm each outage
50
monitors for free
Quorum verification
No false alarms
A failed check alone never triggers an alert. When one probe node sees your site down, a different node re-checks it within seconds - only when it agrees do we open an incident and notify you.
Monitor types
Eight ways to watch
HTTP(S)
Status codes, redirects, response time - the classic website check.
SSL expiry
We watch your certificates and warn you 30, 14, 7, 3 and 1 day ahead.
Keyword
A word that must (or must not) appear in the response.
JSON API
Check a JSON field by path - $.status == "ok".
TCP port
Databases, mail servers, game servers - anything with a port.
Ping
Plain ICMP reachability for servers and routers.
DNS
Records resolve correctly, even against a custom resolver.
Push heartbeat
Your cron job pings us. When it goes quiet, you'll know.
Notifications
Alerts where you already are
Down, recovered, flapping or certificate expiring - delivered to any channel you attach. Repeated flapping is muted into a single digest so your phone doesn't melt.
- Recovery notification with outage duration
- Flapping suppression - one alert instead of fifty
- SSL expiry warnings on schedule
Status pages
Show the world you're up
Every account can publish public status pages - pick the monitors, choose a URL and share 90 days of uptime history with your customers.
Ready? Setup takes a minute.
Create an account, add your first monitor and get your first check within 60 seconds.
Start for free