Website Monitoring Built for Agencies
Know your client's site is down before they do. Get instant alerts for downtime, SSL issues, DNS changes, and unreachable hosts. Set up in 60 seconds.
Everything you need to keep client sites online
Built for agencies and freelancers managing multiple client sites.
Uptime Monitoring
Monitor client sites 24/7 with checks every 30 seconds. Get instant alerts via Slack, Email, or SMS.
SSL Monitoring
Never let a client's certificate expire. Get alerts weeks before expiration.
DNS Tracking
Track DNS records and get notified instantly when something changes.
Keyword Monitoring
Verify page content exists or detect unwanted text like errors or defacements.
API Monitoring
Send custom requests and assert on the JSON response. Catch broken APIs hiding behind a 200 OK.
Ping Monitoring
ICMP echo from every region. Verify servers, network devices and anything that doesn't speak HTTP.
Port Monitoring
TCP connection checks for databases, mail, SSH and any service listening on a specific port.
Heartbeat Monitoring
A dead man's switch for cron jobs and workers. Your job pings a URL, and a missing ping opens an incident.
Cron Job Monitoring
Mirror your crontab. We expect a ping at each scheduled time and alert the moment a run is missed.
Domain Expiration
Track domain registration dates and get alerted well before a domain expires.
Incident Management
Automatic incident timelines and resolution notes for smoother client updates.
Status Pages
Keep clients informed with public or password-protected status pages.
AI Assistant (MCP)
Connect Claude, ChatGPT or any MCP agent. Ask "is anything down?" and triage incidents in plain language.
Team Collaboration
Invite developers and account managers with role-based permissions.
Onboard a client in under a minute
Paste a URL, pick your checks, hit go. That’s the whole flow. No SDKs, no YAML files, no “jump on a call” dance. Your first alert is live before the kickoff meeting ends.
- Monitor every client site from one dashboard
- Branded status pages in one click
- Checks as often as every 30 seconds from 4 regions
- Email, SMS, Slack, Discord and Teams alerts
Keep clients in the loop without another email
Publish a clean, real-time status page for every client. Set expectations during incidents, cut inbound support noise, and send them a link instead of a 2AM apology.
- Custom domain & branding. Host at status.yourclient.com with your logo, colors, and copy, white-labeled end to end.
- Live uptime & incident history. Auto-refreshing uptime, response times, and incident timelines, with no manual updates required.
- Password protection. Keep internal pages behind a passphrase, or publish them to the world. Your call.
“The best monitor I’ve ever used.”
An agency director monitoring 50+ client sites put Sentinel through its paces for a month.
It is by far the best monitor I’ve ever used.
I’ve been using Sentinel for over a month now to monitor our over 50 websites. The region-based monitoring gives you a complete picture and can help troubleshoot issues with your CDN provider’s systems. DNS and domain monitoring provide an extra level of protection against your clients losing their domains or having their DNS hijacked. It easily integrates with Slack. My favorite feature is the Mac menu bar app that keeps your monitors in front of you while allowing you to work on other stuff. If there’s any issue you can open the site’s monitor right from the widget, which is extremely useful. Another key feature is being able to create a monitor page to share with your clients that they will actually use. I could not recommend this product more.
Simple, transparent pricing
10 monitors free, no credit card. Upgrade only as your client list grows.
For agencies and teams managing client portfolios.
FAQ
Frequently asked questions
What is Sentinel?
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How quickly will I know when a site goes down?
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Can I give clients their own status page and reports?
Is there a free plan or a free trial?
How long does it take to set up?
Ready to catch downtime before your clients do?
Start monitoring client sites with confidence. 14-day free trial, cancel anytime.