Why uptime monitoring matters
The worst way to learn your product is down is a customer email. By then the outage has been running for a while, the damage to trust is done, and you are reacting instead of getting ahead of it. Uptime monitoring closes that gap by checking your site from the outside, continuously, so an alert reaches you before your users do.
A real check has to do more than confirm the server answered. A page can return a 200 status while showing an error, a blank body or a maintenance notice. That is why a useful uptime check looks at the response itself, not only the fact that something replied.
What each check verifies
- Status code. The response code is what you expect, not a 500, a 502 or an unexpected redirect.
- Keyword match. An optional string that must appear in the body, so you can confirm the page actually rendered and did not serve an error shell.
- SSL validity. The certificate is valid and not close to expiry. See SSL certificate monitoring for the detail.
- Latency. Response time is recorded on every check, so you can watch for a service that is slowing down before it falls over.
Built to run at scale
Cronaut probes run on Kotlin coroutines through a non-blocking client, so thousands of checks are in flight at once without a thread per check. Reads are capped to a few kilobytes, since a check only needs the status code and an optional keyword, which keeps bandwidth low even at a fast cadence. The probe fleet is horizontally scalable, so adding capacity, and eventually checking from more than one region, is a matter of running more replicas.
Alerts and self-updating incidents
A monitor changing state is the only thing that fires an alert, and flap detection requires a configurable number of consecutive failures first, so a brief blip stays quiet. When a check does go down you are notified by email, Slack, Discord or webhook, and the same state change opens an incident on your public status page. When the site recovers, the incident closes itself. You never post an update by hand.
One engine for uptime, cron and SSL
Uptime checks share a dashboard and a status page with cron and heartbeat monitoring and SSL certificate monitoring, because all three run on the same check engine. Whether the thing that broke is an endpoint, a backup job or an expiring certificate, there is one place to look and one status page that already reflects it.