I have below information. Your question may be different just thought of shairing
It's just a server status if it's up and running to accept commands
Hit url http://127.0.0.1:4725/wd/hub/status
If should return below json string
{"status":0,"value":{"build":{"version":"1.3.4","revision":"c8c79a85fbd6870cd6fc3d66d038a115ebe22efe"}}}