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Email alerts
when your
API endpoint fails

We monitor your API endpoints continuouslyYou get instant email alerts when APIs break

Free 14-day trial · No credit card required

Trusted by thousands of businesses

Setup email alerts for API endpoint failures in seconds

OnlineOrNot continuously monitors your API endpoints from multiple locations worldwide. The moment your API starts returning errors, becomes unresponsive, or fails validation checks, you'll receive an instant email notification with detailed error information.

No more discovering hours later that your customers couldn't use your API or that critical integrations were broken.

Try OnlineOrNot now!

How to get email alerts when your API endpoints fail:

Step 1

Sign up for free

Create your OnlineOrNot account in less than 30 seconds. No credit card required to get started monitoring your APIs.

Step 2

Add your API endpoints

Enter your API endpoint URLs, configure HTTP methods, headers, and response validation rules. Set up custom monitoring intervals and failure thresholds.

Step 3

Get instant detailed alerts

Receive email notifications immediately when your APIs fail, including status codes, response times, error messages, and direct links to detailed monitoring data.

No credit card required.

Frequently asked questions

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Trusted by software teams worldwide

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: 4,164
Detected incidents last week: 775

- 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