CODE: This is on the EVM chain moonbeam network

from websocket import create_connection
import json
url = 'ws://xx.xx.xx.xx:9944/'
ws = create_connection(url)
ws.send(json.dumps({"id": 1, "method": "eth_subscribe", "params": ["newHeads"]}))
print (ws.recv())

Error from above code:

{'error': {'code': -32600, 'message': 'Unsupported JSON-RPC protocol version'}, 'id': 1}



They have linked to the geth docs for the eth_subscribe method.


According to this, expected output is:

>> {"id": 1, "method": "eth_subscribe", "params": ["newHeads", {}]}
<< {"jsonrpc":"2.0","id":1,"result":"0xcd0c3e8af590364c09d0fa6a1210faf5"}

1 Answer 1


Your request should include "jsonrpc":"2.0". E.g.

  "id": 1,
  "method": "eth_subscribe",
  "params": ["newHeads", {}]

See point 4 in https://www.jsonrpc.org/specification

  • Yes, I just figured it out but you are fast. Thanks :)
    – aste123
    Commented Feb 2, 2022 at 15:39

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