This package can monitor the validity of ssl certificates. It can notify you when an invalid certificate is found. It can also warn you if a certificate is going to expire soon.
To get started you should create a monitor. To make life easy for you, if the url starts with https:// the package will automatically enable a certificate check.
If you want to run an certificate check without running the uptime check you can set uptime_check_enabled to 0 in the relevant row in the monitors table.