# QBFT Methods

The `QBFT` API methods provide access to the QBFT consensus engine.

Note

The `QBFT` API methods are not enabled by default for JSON-RPC. To enable the `QBFT` API methods, use the `--rpc-http-api` or `--rpc-ws-api` options.

#### `qbft_discardValidatorVote` <a href="#qbft_discardvalidatorvote" id="qbft_discardvalidatorvote"></a>

Discards a proposal to add or remove a validator with the specified address.

**Parameters**

`address`: *string* - 20-byte address of proposed validator

**Returns**

`result`: *boolean* - indicates if the proposal is discarded

```
curl -X POST --data '{"jsonrpc":"2.0","method":"qbft_discardValidatorVote","params":["0xef1bfb6a12794615c9b0b5a21e6741f01e570185"], "id":1}' http://127.0.0.1:8545
```

#### `qbft_getPendingVotes` <a href="#qbft_getpendingvotes" id="qbft_getpendingvotes"></a>

Returns votes cast in the current epoch.

**Parameters**

None

**Returns**

`result`: *map* of *strings* to *booleans* - map of account addresses to corresponding boolean values indicating the vote for each account; if `true`, the vote is to add a validator. If `false`, the proposal is to remove a validator.

```
curl -X POST --data '{"jsonrpc":"2.0","method":"qbft_getPendingVotes","params":[], "id":1}' http://127.0.0.1:8545
```

#### `qbft_getSignerMetrics` <a href="#qbft_getsignermetrics" id="qbft_getsignermetrics"></a>

Provides the following validator metrics for the specified range:

* Number of blocks from each validator
* Block number of the last block proposed by each validator (if any proposed in the specified range)
* All validators present in the last block of the range

**Parameters**

* `fromBlockNumber`: *string* - integer representing a block number or the string tag `earliest` as described in Block Parameter
* `toBlockNumber`: *string* - integer representing a block number or one of the string tags `latest` or `pending`, as described in Block Parameter

If you specify:

* No parameters, the call provides metrics for the last 100 blocks, or all blocks if there are less than 100 blocks.
* Only the first parameter, the call provides metrics for all blocks from the block specified to the latest block.

**Returns**

`result`: *array* of *objects* - list of validator objects

Note

The proposer of the genesis block has address `0x0000000000000000000000000000000000000000`.

```
curl -X POST --data '{"jsonrpc":"2.0","method":"qbft_getSignerMetrics","params":["1", "100"], "id":1}' http://127.0.0.1:8545
```

#### `qbft_getValidatorsByBlockHash` <a href="#qbft_getvalidatorsbyblockhash" id="qbft_getvalidatorsbyblockhash"></a>

Lists the validators defined in the specified block.

**Parameters**

`block`: *string* - 32-byte block hash

**Returns**

`result`: *array* of *strings* - list of validator addresses

```
curl -X POST --data '{"jsonrpc":"2.0","method":"qbft_getValidatorsByBlockHash","params":["0xbae7d3feafd743343b9a4c578cab5e5d65eb735f6855fb845c00cab356331256"], "id":1}' http://127.0.0.1:8545
```

#### `qbft_getValidatorsByBlockNumber` <a href="#qbft_getvalidatorsbyblocknumber" id="qbft_getvalidatorsbyblocknumber"></a>

Lists the validators defined in the specified block.

**Parameters**

* `blockNumber`: *string* - integer representing a block number or one of the string tags `latest`, `earliest`, or `pending`, as described in Block Parameter

**Returns**

`result`: *array* of *strings* - list of validator addresses

```
curl -X POST --data '{"jsonrpc":"2.0","method":"qbft_getValidatorsByBlockNumber","params":["latest"], "id":1}' http://127.0.0.1:8545
```

#### `qbft_proposeValidatorVote` <a href="#qbft_proposevalidatorvote" id="qbft_proposevalidatorvote"></a>

Proposes to add or remove a validator with the specified address.

**Parameters**

* `address`: *string* - account address
* `proposal`: *boolean* - `true` to propose adding validator or `false` to propose removing validator

**Returns**

```
curl -X POST --data '{"jsonrpc":"2.0","method":"qbft_proposeValidatorVote","params":["42d4287eac8078828cf5f3486cfe601a275a49a5",true], "id":1}' http://127.0.0.1:8545
```

<br>