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Heartbeat monitoring
for your critical services

We monitor that your servers, applications, and devices check in regularlyYou get alerted when heartbeats stop via email, Slack, PagerDuty, and more
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Trusted by thousands of businesses

Everything you need

Heartbeat monitoring that just works

Simple, reliable, and powerful heartbeat monitoring for modern infrastructure. No complex setup, no vendor lock-in, just reliable monitoring that scales with your business.

Monitor anything with a heartbeat
Servers, applications, IoT devices, backup jobs, data pipelines - if it can send an HTTP request, OnlineOrNot can monitor it. One simple curl command is all it takes.
Zero-configuration setup
No complex configuration files or SDKs required. Create a monitor, get a URL, send a ping. Your heartbeat monitoring is live in under 60 seconds.
Intelligent failure detection
Advanced scheduling with cron expressions, grace periods for late heartbeats, and smart alerting that reduces false positives while catching real issues.
Instant multi-channel alerts
Get notified immediately via Email, SMS, Slack, Discord, Microsoft Teams, PagerDuty, OpsGenie, Grafana OnCall, Incident.io, and more.
Developer-friendly API
Full REST API, webhooks, and open-source CLI tools. Integrate heartbeat monitoring into your existing workflows and infrastructure-as-code.
Private status pages
Share real-time status with your team and stakeholders. Perfect for internal infrastructure monitoring and service health dashboards.
Mobile & IoT ready
Lightweight heartbeat endpoints perfect for mobile apps, embedded devices, and IoT sensors. Monitor edge infrastructure with ease.
Enterprise integrations
Seamlessly integrate with your existing on-call tools like PagerDuty, Incident.io, and Opsgenie. Built for teams that take reliability seriously.

Common heartbeat monitoring use cases

See how teams use OnlineOrNot to monitor everything from servers to IoT devices

Server Health Monitoring

Send periodic heartbeats from your servers to ensure they're online and responsive.

@hourly curl https://hb.onlineornot.com/abc123

Application Health Checks

Monitor critical application processes, background workers, and service health.

app.health_check() → ping heartbeat endpoint

IoT Device Monitoring

Track the status of remote devices, sensors, and embedded systems.

ESP32 → periodic WiFi heartbeat → instant alerts

Data Pipeline Monitoring

Ensure ETL jobs, data syncs, and batch processes complete successfully.

pipeline.on_success() → heartbeat ping

Software teams ❤️ OnlineOrNot

OnlineOrNot is built for scale and runs millions of uptime checks every week. Thousands of software teams, including some of the world's leading brands have already made the switch from other uptime monitors.

Uptime Checks last week
11.8M
Users
3,943
Detected incidents last week
774

    • OnlineOrNot has been absolutely fantastic for my bot, Noti. It completely transformed the way I monitor online services.

      The real-time notifications keep me in the loop about any downtime, allowing me to take immediate action. If you're looking for a reliable way to monitor your project's status, I highly suggest using OnlineOrNot.

      Adam H
      Maker of Noti

    • Bet on indie hackers 🚀

      I tried @RozenMD's OnlineOrNot uptime monitoring, and for a few days got notifications of 2min down time.

      I thought that OnlineOrNot was wrong as Uptime Robot wasn't reporting anything.

      Turns out it was the other way around.

      Khaled Bentoumi
      Founder of Data to Page

    • We've been using OnlineOrNot and it has been a life saver.

      It, by far, has been one of the most responsive uptime services we've tried and it only gets better and better as time goes on.

      Alex Bowles
      Founder of Casterlabs

    • I just set up some site aliveness checks for @Archium_io with @RozenMD's OnlineOrNot.

      Took me less than five minutes and it was completely self-explanatory, not to mention gorgeous. Seriously good experience.

      Great job, Max! 👏👏

      Graham Lea
      Founder of Archium.io

    • OnlineOrNot by @RozenMD is all one needs

      It is easy to set up and very reliable. I have been using it for almost an year now.

      Rajat Saxena
      Founder of CourseLit

    • I'm using OnlineOrNot to monitor my @cloakist customers' sites, so I can respond quickly if they stop working

      Love it. Super clean interface, very intuitive. Particularly impressed at how it can wait for full page load

      Thanks @RozenMD for making this awesome tool!

      Louis Barclay
      Founder of Cloakist

    • OnlineOrNot does the job for me.

      Charles Miller
      Software Architect at Atlassian
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