NSClient is an agent designed originally to work with Nagios but has since evolved into a fully fledged monitoring agent which can be used with numerous monitoring tools (like Icinga, Naemon, OP5, NetEye Opsview etc). If you want more in-depth information see the documentation instead.
I know NSClient++ can seem daunting. But is really is not, especially not now with all the documentation and tutorials. But it is "open ended" so before you start be sure to read though the tutorial for your scenario and we are sure you will be on a journey towards #MonitoringLove.
Getting involved is easy! If you have questions or want to connect with the community the forums is the place to go. Or if you have issues, feature requests or want to access the code and we are on github. But we are also equally interested in all contributions big or small.