Website developers should have an alerting mechanism for the important features of the website. If we are seeing more user error than usual, then it should alert developers so that they can look at the error and work towards fixing it. This is called early detection.
Check the vitals and heartbeat of the website. Check the health of the server that is hosting the website. In server monitoring, the two important parts are CPU usage and memory usage.
Uptime is the period when your Website is up and running. Checking the uptime is relatively easy; search online for an Uptime Checker Tool. You only have to submit Your URL to check the availability of your website. Depending on the checker you are using, click the Analyze button, then the tool runs an analysis.
After the website uptime test, you will immediately receive the results of the standard operating state of your website. You will also find other details about the website.
Be vigilant on social media like Twitter and Reddit. There are some community websites like a down detector, etc. It is also good to listen to the users of the website and take their feedback regularly. If users have a problem with any feature, they will usually complain about one of the community forums. So, having a dedicated employee to check the community forums and understanding the user requirement, will make the website more usable.