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
12
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
Twelve 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.
Web journey
A real browser walks your site like a customer: add to cart, open the checkout, verify it renders.
Product feed
Heureka, Zbozi.cz and Google Merchant XML: validity and sudden item drops, before comparators drop you.
Domain expiry
WHOIS watch on your domain's expiry date. An expired domain takes the site and e-mail down at once.
Blacklists & Safe Browsing
Spam blacklists and Google's dangerous-site flag: the silent killers of deliverability and traffic.
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.
Pricing
Start free, upgrade when you grow
The core stays free: 50 monitors, 8 monitor types, all alert channels and a public status page. Paid plans add speed, capacity and more check types.
Free
€0forever
- 50 monitors
- Checks every 5 minutes
- 8 monitor types incl. domain expiry
- 1 public status page
E-shop
€10/ month
or €100 / year with a one-hour setup consultation
- 20 monitors, 1-minute website checks
- Web journeys: cart and checkout walk-throughs
- Feed, blacklist and domain expiry watch
- Lost-revenue estimates and monthly reports
Business
€14/ month
- 300 monitors
- Checks every minute
- All monitor types incl. web journeys
- 20 status pages and custom domains
Prices excl. VAT, billed in EUR (CZK for Czech accounts). Cancel anytime - monitors keep running, only the limits return to Free.
Ready? Setup takes a minute.
Create an account, add your first monitor and get your first check within 60 seconds.
Start for free