For DevOps and SRE
Uptime Monitoring for DevOps Teams
Consensus from four regions before anyone gets alerted, 30-second checks, PagerDuty and Terraform. Monitoring that treats you like the person responsible for uptime, because you are.
Why DevOps teams pick Sentinel
Alerts you can act on at 3am
A single probe in one data centre sees its own network problems as your outage. Sentinel checks from four regions and only opens an incident when three of them agree, so an alert means the service is down, not that a route in Virginia hiccuped.
- Consensus across regions before anyone gets alerted
- Monitors as code with the Terraform provider and the CLI
- Deploy markers on every chart, straight from GitHub
Built for the on-call rotation
Everything an alert needs to be right
Multi-region consensus
Every check runs from Virginia, Oregon, Germany and Singapore. An incident needs three of the four to agree, which is what keeps false alerts out of your on-call rotation.
Down to 30 seconds
Free checks every five minutes, Starter and Pro every minute, Business every 30 seconds. Pick the cadence per monitor, so the checkout API runs hot and the marketing site doesn't.
PagerDuty, Slack, webhooks
Open and resolve PagerDuty incidents through the Events API, post to Slack, Discord or Teams, or send signed JSON to your own endpoint. Routing is per monitor, not per account.
Monitors as code
Declare monitors, groups and alert routing in Terraform or script them from the CLI. The same REST API sits under the dashboard, with write access on every plan, including Free.
Deploy markers
Install the GitHub app and every deployment is drawn on the response-time charts and cited on incidents, so the question 'what changed?' already has an answer.
Heartbeats for the jobs nobody watches
Cron jobs, queue workers and backups ping Sentinel when they finish. Miss a ping and you hear about it. Dead-man switches for the parts of the system that don't serve HTTP.
How does Sentinel avoid false alerts?
Each check runs from four regions. A failure in one region is recorded but doesn't open an incident on its own. Only when three of the four regions fail the same check does Sentinel mark the monitor down and send alerts, so a flaky route near one probe never alerts you.
What's the fastest check interval?
30 seconds on the Business plan. Starter and Pro check every minute, and the Free plan every five minutes. The interval is set per monitor, so you can run critical endpoints at the fastest cadence your plan allows and leave low-stakes endpoints slower.
Does it integrate with PagerDuty?
Yes. Sentinel opens a PagerDuty incident through the Events API v2 when a monitor goes down and resolves it on recovery. You connect a PagerDuty service to a team and choose which monitors route to it. PagerDuty is included on the Business plan.
Can I manage monitors with Terraform?
Yes. The Sentinel Terraform provider is on the Terraform Registry and covers monitors, groups and notification settings, so monitoring lives in the same pull requests as the infrastructure it watches. There's also a CLI on npm and a REST API with full read and write access on every plan.
Can it monitor things that aren't websites?
Yes. Beyond HTTP checks there are ping and TCP port monitors, DNS record and SSL certificate checks, JSON assertions against API responses, and heartbeat monitors for cron jobs and queue workers that report in by pinging a URL.
Where do the checks come from?
From Sentinel's own probes in four regions across North America, Europe and Asia. The probe IPs are published so you can allow-list them, and the same probes are available on demand for a one-off check of any URL.
Alerts that mean something
Add your first endpoints in a minute, or declare them in Terraform. Free to start, full API included.
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