If you mean making an http / https query to a website to see if it responds, yes.
You do this using the “Services” feature using Nagios plugins:
This may require you to install the nagios plugins in your operating system, which will vary depending on what Linux distribution you’re using.
I run LibreNMS on Ubuntu server and from memory I installed an apt package called monitoring-plugins.
When the plugins are installed and you have Services enabled in LibreNMS you can create a service. For example here is one testing google:
Here is what the results look like when there are successful responses:
To be alerted if this fails you will need to set up some alerts and possibly alert template for services. There are some templates in the alert template library to alert on services that are in warning or critical state.
Nagios plugins are not part of LibreNMS so you will need to google for them to find their documented command line options. (Or run them manually from the command line to explore their options)