Shopify’s own uptime is excellent, and its status page will tell you when the platform is having a bad day. Neither of those facts covers the ways a specific store stops answering: a certificate that expired on a custom domain, a DNS record that changed, a password page left on after a theme deploy, a redirect loop, or an app that returns a 500 on the cart. Uptime monitoring watches your store, from outside, on the domain your customers actually type.
A health check is an HTTP request from outside your infrastructure to a URL you nominate, on a fixed interval, recording the status code and how long the response took. If the response is not a success, or does not arrive within the timeout, the check has failed.
The interesting engineering is in what happens next. A single failed request is not an outage — networks drop packets, edge nodes recycle, a CDN node has a bad second. A monitor that alerts on the first failure trains you to ignore it, which is worse than having no monitor at all. Cassian Sentinel™ waits 30 seconds and re-checks before it raises anything.
Shopify’s status page answers one question: is Shopify healthy? These are the failures that leave it green while your store is not selling.
This is the limitation worth being honest about, because it is the reason uptime monitoring gets bought and then quietly disappoints. An HTTP check confirms a page was returned. It cannot confirm that the add-to-cart button works, that the payment gateway is authorising, or that the checkout is completing — those are all 200 OK responses on the way to zero orders.
The check that catches that failure is a different one: watching order volume against its own historical baseline and alerting when a period that should have orders has none. Cassian™ runs both, and the order check is on every plan including the free one.
Two of the most damaging store outages are also the most predictable, because both have a known expiry date. Cassian Sentinel™ inspects the TLS certificate by direct connection and checks domain registration expiry daily, then counts down — so the alert arrives while renewing is still routine rather than urgent.
What Cassian™ actually does
Cassian Sentinel™ sends an HTTP health check every 5 minutes, and every minute on the top plans, from outside your infrastructure.
Protector and Guardian: 5 minutes. Prime and Enterprise: 1 minute. Not included on Inspector or Analyst.
On a failed check, Cassian™ waits 30 seconds and re-checks before opening an incident — so a single dropped request does not become a false alarm.
Protector and above.
Cassian™ inspects your TLS certificate directly and checks domain registration expiry daily, alerting on the countdown rather than on the failure.
Protector and above.
Response times are recorded on every check, so a store that is getting slower shows up as a trend before it shows up as an outage.
Protector and above.
Separately from uptime, Cassian™ watches order volume against a weighted historical baseline and raises a critical alert when a period that should have orders has none — the failure an HTTP check cannot see.
Every plan, including free.
FAQ
Free scan, results in minutes. Zero-order alerts on every plan, including the free one.
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