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CometBFT RPC

The CometBFT RPC allows you to query transactions, blocks, consensus state, broadcast transactions, etc.

The latest CometBFT RPC documentations can be found here. CometBFT supports the following RPC protocols:

  • URI over HTTP
  • JSON-RPC over HTTP
  • JSON-RPC over Websockets

The docs will contain an interactive Swagger interface.

URI/HTTP

A GET request with arguments encoded as query parameters:

curl localhost:26657/block?height=5

RPC/HTTP

JSONRPC requests can be POST'd to the root RPC endpoint via HTTP. See the list of supported CometBFT RPC endpoints using Swagger here.

RPC/Websocket

Cosmos and CometBFT Events

Events are objects that contain information about the execution of the application and are triggered after a block is committed. They are mainly used by service providers like block explorers and wallet to track the execution of various messages and index transactions. You can get the full list of event categories and values here.

More on Events:

Subscribing to Events via Websocket

CometBFT Core provides a Websocket connection to subscribe or unsubscribe to CometBFT Events. To start a connection with the CometBFT websocket you need to define the address with the --rpc.laddr flag when starting the node (default tcp://127.0.0.1:26657):

haqqd start --rpc.laddr="tcp://127.0.0.1:26657"

Then, start a websocket subscription with ws

# connect to tendermint websocket at port 8080
ws ws://localhost:8080/websocket

# subscribe to new CometBFT block headers
> { "jsonrpc": "2.0", "method": "subscribe", "params": ["tm.event='NewBlockHeader'"], "id": 1 }

The type and attribute value of the query allow you to filter the specific event you are looking for. For example, an Ethereum transaction on HAQQ (MsgEthereumTx) triggers an event of type ethermint and has sender and recipient as attributes. Subscribing to this event would be done like so:

{
"jsonrpc": "2.0",
"method": "subscribe",
"id": "0",
"params": {
"query": "tm.event='Tx' AND ethereum.recipient='hexAddress'"
}
}

where hexAddress is an Ethereum hex address (eg: 0x1122334455667788990011223344556677889900).

The generic syntax looks like this:

{
"jsonrpc": "2.0",
"method": "subscribe",
"id": "0",
"params": {
"query": "tm.event='<event_value>' AND eventType.eventAttribute='<attribute_value>'"
}
}

List of CometBFT Events

The main events you can subscribe to are:

  • NewBlock: Contains events triggered during BeginBlock and EndBlock.
  • Tx: Contains events triggered during DeliverTx (i.e. transaction processing).
  • ValidatorSetUpdates: Contains validator set updates for the block.
tip

👉 The list of events types and values for each Cosmos SDK module can be found in the Modules Specification section. Check the Events page to obtain the event list of each supported module on HAQQ Network.

List of all CometBFT event keys:

Event TypeCategories
Subscribe to a specific event"tm.event"block
Subscribe to a specific transaction"tx.hash"block
Subscribe to transactions at a specific block height"tx.height"block
Index BeginBlock and Endblock events"block.height"block
Subscribe to ABCI BeginBlock events"begin_block"block
Subscribe to ABCI EndBlock events"end_block"consensus

Below is a list of values that you can use to subscribe for the tm.event type:

Event ValueCategories
New block"NewBlock"block
New block header"NewBlockHeader"block
New Byzantine Evidence"NewEvidence"block
New transaction"Tx"block
Validator set updated"ValidatorSetUpdates"block
Block sync status"BlockSyncStatus"consensus
lock"Lock"consensus
New consensus round"NewRound"consensus
Polka"Polka"consensus
Relock"Relock"consensus
State sync status"StateSyncStatus"consensus
Timeout propose"TimeoutPropose"consensus
Timeout wait"TimeoutWait"consensus
Unlock"Unlock"consensus
Block is valid"ValidBlock"consensus
Consensus vote"Vote"consensus

Example

ws ws://localhost:26657/websocket
> { "jsonrpc": "2.0", "method": "subscribe", "params": ["tm.event='ValidatorSetUpdates'"], "id": 1 }

Example 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"
}
]
}
}
}
}
tip

Note: When querying Ethereum transactions versus Cosmos transactions, the transaction hashes are different. When querying Ethereum transactions, users need to use event query. Here's an example with the CLI:

curl -X GET "http://localhost:26657/tx_search?query=ethereum_tx.ethereumTxHash%3D0x8d43464891fac6c113e809e14dff1a3e608eae124d629799e42ca0e36562d9d7&prove=false&page=1&per_page=30&order_by=asc" -H "accept: application/json"