Configure an SSL/HTTP-Check

Monitor website availability and SSL certificate expiry with an SSL/HTTP check

Written By Erdinc Akay

Last updated 25 days ago

An SSL/HTTP check monitors whether a website or web service is reachable and whether its security certificate is still valid. If the site goes down or the certificate is about to expire, you get an alert.

What this check does

  • Website availability: sends a request to a URL and checks whether the response is what you expect (usually a "200 OK" status).
  • Certificate expiry: checks how many days are left before the site's SSL/TLS certificate expires.

Before you start

You need the full URL of the site or service you want to monitor, including https:// (for example, https://portal.example.com).

Steps

  1. Go to Devices and open the device that will perform the checks.
  2. Click the Checks tab → Add Check → SSL / HTTP.
  3. Add one or more endpoints to monitor:
FieldWhat to enter
URLThe full address to check, e.g. https://portal.example.com
Expected status codeLeave at 200 unless the site intentionally returns a different code
Check SSL certificate expiryLeave enabled to monitor certificate expiry (recommended)
Warning threshold (days before expiry)Alert as warning when the certificate expires within this many days (default: 30)
Error threshold (days before expiry)Alert as error when the certificate expires within this many days (default: 14)

The two threshold fields only appear when Check SSL certificate expiry is enabled. If you turn that option off, the warning and error day fields are hidden.

Add Check → SSL / HTTP with an empty Endpoints-to-monitor list, Add Check disabled until an endpoint is added.
  1. Click Add Check to confirm.

What triggers an alert?

ConditionSeverity
Site returns an unexpected status code (e.g. 500 instead of 200)Critical
Certificate expires within the warning thresholdWarning
Certificate expires within the error thresholdCritical
Site is unreachable (connection fails or times out)Error

Tips

  • You can monitor multiple URLs in a single check — octoja checks them all and reports the worst result.
  • The check does not follow redirects. If your site redirects (e.g. http:// → https://), enter the final URL.
  • A typical setup: set Warning to 30 days and Error to 14 days.

After the first check interval, the result appears in the device's Checks tab.

See also: SSL/HTTP-Check Reference