You can sniff all incoming measurement packets for your units, if you dispose of superadmin, admin or analytics roles. First, log in via the standard API and obtain the session object. Find the token value and open (secure) WebSocket at /sn/ws/TOKEN/sniffer.

The socket reads/writes measurement packets (in binary format) as specified in the technical documentation. If you send a packet via the socket, it is returned back to you immediately. You can use this for a ping-pong to check the connectivity between your client and the server.