Radar is a desktop application available for Windows, macOS, and Linux. It lets you check the things that matter to you the most from the menubar. You can also setup threshold notifications and visualize the change of data over time on a line chart.
You can check menubar from anywhere on your system. Radar lives quietly in the menubar. You can summon it when needed from any application by clicking the icon or using the global keyboard shortcut.
The data point you are interested in is fetched from an API. Radar can connect with any API and call it periodically when auto-refresh is enabled or on-demand.