github.com/badrootd/celestia-core@v0.0.0-20240305091328-aa4207a4b25d/docs/core/subscription.md (about) 1 --- 2 order: 7 3 --- 4 5 # Subscribing to events via Websocket 6 7 CometBFT emits different events, which you can subscribe to via 8 [Websocket](https://en.wikipedia.org/wiki/WebSocket). This can be useful 9 for third-party applications (for analysis) or for inspecting state. 10 11 [List of events](https://godoc.org/github.com/cometbft/cometbft/types#pkg-constants) 12 13 To connect to a node via websocket from the CLI, you can use a tool such as 14 [wscat](https://github.com/websockets/wscat) and run: 15 16 ```sh 17 wscat -c ws://127.0.0.1:26657/websocket 18 ``` 19 20 NOTE: If your node's RPC endpoint is TLS-enabled, utilize the scheme `wss` instead of `ws`. 21 22 You can subscribe to any of the events above by calling the `subscribe` RPC 23 method via Websocket along with a valid query. 24 25 ```json 26 { 27 "jsonrpc": "2.0", 28 "method": "subscribe", 29 "id": 0, 30 "params": { 31 "query": "tm.event='NewBlock'" 32 } 33 } 34 ``` 35 36 Check out [API docs](https://docs.cometbft.com/v0.34/rpc/) for 37 more information on query syntax and other options. 38 39 You can also use tags, given you had included them into DeliverTx 40 response, to query transaction results. See [Indexing 41 transactions](./indexing-transactions.md) for details. 42 43 ## ValidatorSetUpdates 44 45 When validator set changes, ValidatorSetUpdates event is published. The 46 event carries a list of pubkey/power pairs. The list is the same 47 CometBFT receives from ABCI application (see [EndBlock 48 section](https://github.com/cometbft/cometbft/blob/v0.34.x/spec/abci/abci++_methods.md#endblock) in 49 the ABCI spec). 50 51 Response: 52 53 ```json 54 { 55 "jsonrpc": "2.0", 56 "id": 0, 57 "result": { 58 "query": "tm.event='ValidatorSetUpdates'", 59 "data": { 60 "type": "tendermint/event/ValidatorSetUpdates", 61 "value": { 62 "validator_updates": [ 63 { 64 "address": "09EAD022FD25DE3A02E64B0FE9610B1417183EE4", 65 "pub_key": { 66 "type": "tendermint/PubKeyEd25519", 67 "value": "ww0z4WaZ0Xg+YI10w43wTWbBmM3dpVza4mmSQYsd0ck=" 68 }, 69 "voting_power": "10", 70 "proposer_priority": "0" 71 } 72 ] 73 } 74 } 75 } 76 } 77 ```