Customer-backed and built to last. Read why

Synthetic monitoring
for production teams

Monitor websites, APIs, and browser flows from outside your appGet alerted when production breaks, before customers tell you
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OnlineorNot Uptime Checks screenshot

Trusted by thousands of businesses

Know when production works, not just when it responds

Synthetic monitoring simulates the checks your customers and systems depend on: loading pages, validating APIs, running browser checks, and confirming scheduled jobs are alive.

OnlineOrNot gives small teams the practical parts of synthetic monitoring without forcing them into a full observability platform: uptime checks, API checks, real Chrome browser checks, global regions, retries, and alerts in the tools your team already uses.

What synthetic monitoring should cover

Start with the paths that create incidents: homepage outages, broken APIs, blank JavaScript apps, failed login, checkout, and dashboards.

Catch silent frontend failures

Run Chrome-based checks that verify JavaScript rendered, expected text appeared, and critical pages still work after deploys.

Verify APIs from the outside

Continuously test REST and GraphQL endpoints from global regions with status code, response body, and authentication checks.

Alert before customers report it

Retry failures, reduce false positives, and notify Slack, PagerDuty, Discord, Microsoft Teams, SMS, email, or webhooks.

Synthetic monitoring, without the enterprise baggage

Datadog, Checkly, Grafana, and other platforms are powerful, but many teams only need reliable checks, clear alerts, and a fast way to prove production still works.

Synthetic monitoring vs uptime monitoring

Uptime monitoring checks that a URL responds. Synthetic monitoring goes further by testing APIs, rendered pages, and user-critical workflows.

Synthetic monitoring vs real user monitoring

Real user monitoring shows what happened to visitors. Synthetic monitoring proactively simulates checks before real users hit the broken path.

Synthetic monitoring vs end-to-end tests

End-to-end tests usually run in CI. Synthetic monitors keep running after release, from external regions, with production alerting attached.

Create your first monitor

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
17.1M
Users
6,733
Detected incidents last week
2,193

    • 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
Create an uptime check

Free 14-day trial · No credit card required

What makes OnlineOrNot different?

There are hundreds of uptime monitoring tools out there. Believe me, I know. I built OnlineOrNot because none of them felt right.

Some were too complicated, designed for mega-corporations with thousands of employees. Others were too simple, didn't offer the features I needed, or were just plain unreliable.

It turns out thousands of other freelance developers, agencies, founders, and software teams felt the same way.

— Max, the guy who runs OnlineOrNot

Create an uptime check

Free 14-day trial · No credit card required

Open to feedback.
Something in OnlineOrNot not working as expected? Have an idea for a new feature? I want to hear from you!
Daily releases.
Almost every feature in OnlineOrNot came from customer feedback. If it doesn't support your use case today, chances are it will soon.
Well-documented.
Every person is different - what's intuitive to one person isn't to another. OnlineOrNot documents every feature so that you're not left guessing how it works.
We'll be here for a while.
OnlineOrNot is 100% backed by its customers with no plans to raise venture funding, so it is built to last.
Public API & Open-source CLI.
Use the public API to integrate OnlineOrNot into your own systems, or use our open-source CLI to check status from your terminal.
Your data stays yours.
We never sell your data to third parties or use it for purposes beyond improving OnlineOrNot.

Synthetic monitoring tools in OnlineOrNot

Combine uptime, API, browser, cron, and status page workflows without stitching together multiple products

Website monitoring

Run fast uptime checks from global regions

API monitoring

Validate status codes, response bodies, and API assertions

Browser checks

Run real Chrome checks for JavaScript-heavy user flows

Cron job monitoring

Know when scheduled jobs stop checking in

Status pages

Communicate incidents from the same monitoring workflow

Free monitoring tools

Try alerting workflows before creating a monitor

Start synthetic monitoring
before production breaks silently

Run website checks, API checks, real browser checks, cron monitoring, and status pages from one place.

See pricing