Use the command line to open a WebSocket connection to the Sandbox BTC Market Data Feed.
See the WebSocket API reference for more details.

​
➊ Install WebSocket Client

The quickest way to open a connection is by using wscat, which runs in the terminal. Using the Python websocket-client package requires a bit of code and the Python shell.
Open the terminal and install wscat using the -g (global) flag.
npm install -g wscat
Ensure wscat is working. If you see the version number, the module is working:
wscat --version
Leave the terminal window open.

​
➋ Connect to Sandbox Feed

Open a long-lived connection to the Sandbox BTC Market Data Feed. 
wscat --connect wss://ws.sandbox.paxos.com/marketdata/BTCUSD

​
➌ Review Sandbox Feed

If everything worked, you see the initial SNAPSHOT and then an UPDATE stream in the terminal.
Sandbox BTC Market Data Feed (wscat)
Connected (press CTRL+C to quit)
< {
    "type": "SNAPSHOT",
    "market": "BTCUSD",
    "bids": [
      {
        "price": "19994.25",
        "amount": "0.7755"
      },
      {
        "price": "19993.75",
        "amount": "0.83676985"
      },
      ...
    ],
    "asks": [
      {
        "price": "19994.5",
        "amount": "0.97548541"
      },  
      {
        "price": "19996",
        "amount": "1.135"
      },
      ...
    ],
    "final_snapshot": true
  }

< {
    "type": "UPDATE",
    "market": "BTCUSD",
    "side": "BUY",
    "price": "19958.5",
    "amount": "0.62649999"
  }

< {
    "type": "UPDATE",
    "market": "BTCUSD",
    "side": "SELL",
    "price": "20115.25",
    "amount": "0"
  }
  ...