tendermint/docs/app-dev/subscribing-to-events-via-websocket.md

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Subscribing to events via Websocket

Tendermint emits different events, to which you can subscribe via Websocket. This can be useful for third-party applications (for analysis) or inspecting state.

List of events

You can subscribe to any of the events above by calling subscribe RPC method via Websocket.

{
    "jsonrpc": "2.0",
    "method": "subscribe",
    "id": 0,
    "params": {
        "query": "tm.event='NewBlock'"
    }
}

Check out API docs for more information on query syntax and other options.

You can also use tags, given you had included them into DeliverTx response, to query transaction results. See Indexing transactions for details.

ValidatorSetUpdates

When validator set changes, ValidatorSetUpdates event is published. The event carries a list of pubkey/power pairs. The list is the same Tendermint receives from ABCI application (see EndBlock section in the ABCI spec).

Response:

{
    "jsonrpc": "2.0",
    "id": 0,
    "result": {
        "query": "tm.event='ValidatorSetUpdates'",
        "data": {
            "type": "tendermint/event/ValidatorSetUpdates",
            "value": {
              "validator_updates": [
                {
                  "address": "09EAD022FD25DE3A02E64B0FE9610B1417183EE4",
                  "pub_key": {
                    "type": "tendermint/PubKeyEd25519",
                    "value": "ww0z4WaZ0Xg+YI10w43wTWbBmM3dpVza4mmSQYsd0ck="
                  },
                  "voting_power": "10",
                  "proposer_priority": "0"
                }
              ]
            }
        }
    }
}