> ## Documentation Index
> Fetch the complete documentation index at: https://docs.quantumapi.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Blocks

> Query chain ID, block numbers, headers, full blocks, and uncle data

## qc\_chainId

Returns the EIP-155 chain ID. Quantum Chain mainnet is `20803` (`0x5143`).

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_chainId","params":[],"id":1}'
```

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x5143"
}
```

***

## qc\_blockNumber

Returns the number of the most recent block.

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_blockNumber","params":[],"id":1}'
```

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x1a4"
}
```

***

## qc\_syncing

Returns `false` if the node is fully synced, or an object with sync progress.

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_syncing","params":[],"id":1}'
```

**When synced:**

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": false
}
```

**When syncing:**

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "startingBlock": "0x0",
    "currentBlock": "0x1a4",
    "highestBlock": "0x3e8"
  }
}
```

***

## qc\_getBlockByNumber

Returns a block by number. Set `fullTx` to `true` to include full transaction objects instead of just hashes.

| Parameter     | Type      | Description                                                                               |
| ------------- | --------- | ----------------------------------------------------------------------------------------- |
| `blockNumber` | `string`  | Block number (hex) or tag: `"latest"`, `"pending"`, `"earliest"`, `"finalized"`, `"safe"` |
| `fullTx`      | `boolean` | If `true`, return full transaction objects                                                |

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_getBlockByNumber","params":["latest", false],"id":1}'
```

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "number": "0x1a4",
    "hash": "0xabc...123",
    "parentHash": "0xdef...456",
    "timestamp": "0x65f5e100",
    "gasUsed": "0x5208",
    "gasLimit": "0x1c9c380",
    "miner": "0x0000000000000000000000000000000000000000",
    "transactions": ["0x789...abc"]
  }
}
```

***

## qc\_getBlockByHash

Returns a block by its hash. Same parameters as `qc_getBlockByNumber` but accepts a block hash.

| Parameter   | Type      | Description                                |
| ----------- | --------- | ------------------------------------------ |
| `blockHash` | `string`  | 32-byte block hash (hex)                   |
| `fullTx`    | `boolean` | If `true`, return full transaction objects |

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_getBlockByHash","params":["0xabc...123", true],"id":1}'
```

***

## qc\_getHeaderByNumber

Returns a block header by number.

| Parameter     | Type     | Description               |
| ------------- | -------- | ------------------------- |
| `blockNumber` | `string` | Block number (hex) or tag |

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_getHeaderByNumber","params":["latest"],"id":1}'
```

***

## qc\_getHeaderByHash

Returns a block header by its hash.

| Parameter   | Type     | Description              |
| ----------- | -------- | ------------------------ |
| `blockHash` | `string` | 32-byte block hash (hex) |

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_getHeaderByHash","params":["0xabc...123"],"id":1}'
```

***

## qc\_getUncleCountByBlockNumber

Returns the number of uncles in a block by block number.

| Parameter     | Type     | Description               |
| ------------- | -------- | ------------------------- |
| `blockNumber` | `string` | Block number (hex) or tag |

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_getUncleCountByBlockNumber","params":["latest"],"id":1}'
```

***

## qc\_getUncleCountByBlockHash

Returns the number of uncles in a block by block hash.

| Parameter   | Type     | Description              |
| ----------- | -------- | ------------------------ |
| `blockHash` | `string` | 32-byte block hash (hex) |

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_getUncleCountByBlockHash","params":["0xabc...123"],"id":1}'
```

***

## qc\_getUncleByBlockNumberAndIndex

Returns uncle block data by block number and uncle index.

| Parameter     | Type     | Description                |
| ------------- | -------- | -------------------------- |
| `blockNumber` | `string` | Block number (hex) or tag  |
| `uncleIndex`  | `string` | Uncle position index (hex) |

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_getUncleByBlockNumberAndIndex","params":["latest","0x0"],"id":1}'
```

***

## qc\_getUncleByBlockHashAndIndex

Returns uncle block data by block hash and uncle index.

| Parameter    | Type     | Description                |
| ------------ | -------- | -------------------------- |
| `blockHash`  | `string` | 32-byte block hash (hex)   |
| `uncleIndex` | `string` | Uncle position index (hex) |

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"qc_getUncleByBlockHashAndIndex","params":["0xabc...123","0x0"],"id":1}'
```