> ## 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.

# Execution

> Read-only contract calls, access list generation, and sync status

## qc\_call

Executes a message call immediately without creating a transaction on the blockchain. Commonly used to read data from smart contracts.

| Parameter     | Type     | Description               |
| ------------- | -------- | ------------------------- |
| `txObject`    | `object` | Transaction call object   |
| `blockNumber` | `string` | Block number (hex) or tag |

The transaction call object supports these fields:

| Field      | Type     | Required | Description                 |
| ---------- | -------- | -------- | --------------------------- |
| `from`     | `string` | No       | Sender address              |
| `to`       | `string` | Yes      | Contract address            |
| `gas`      | `string` | No       | Gas limit (hex)             |
| `gasPrice` | `string` | No       | Gas price (hex)             |
| `value`    | `string` | No       | Value in wei (hex)          |
| `data`     | `string` | No       | ABI-encoded call data (hex) |

```bash theme={null}
curl -X POST https://api.quantumapi.io/v1/rpc \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "qc_call",
    "params": [{
      "to": "0x1234567890abcdef1234567890abcdef12345678",
      "data": "0x70a08231000000000000000000000000ff81e5c74e14db5b4ee407d66b1b063c8f305c51"
    }, "latest"],
    "id": 1
  }'
```

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x00000000000000000000000000000000000000000000000000000000000003e8"
}
```

<Tip>
  The `data` field above is an ABI-encoded `balanceOf(address)` call. Use `cast calldata` or an ABI encoder to build these.
</Tip>

***

## qc\_createAccessList

Creates an EIP-2930 access list for a transaction. The access list identifies storage slots and addresses the transaction will access, which can reduce gas costs.

| Parameter     | Type     | Description               |
| ------------- | -------- | ------------------------- |
| `txObject`    | `object` | Transaction call object   |
| `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_createAccessList",
    "params": [{
      "from": "0xff81e5c74e14db5b4ee407d66b1b063c8f305c51",
      "to": "0x1234567890abcdef1234567890abcdef12345678",
      "data": "0x70a08231000000000000000000000000ff81e5c74e14db5b4ee407d66b1b063c8f305c51"
    }, "latest"],
    "id": 1
  }'
```

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "accessList": [
      {
        "address": "0x1234567890abcdef1234567890abcdef12345678",
        "storageKeys": [
          "0x0000000000000000000000000000000000000000000000000000000000000001"
        ]
      }
    ],
    "gasUsed": "0x5c68"
  }
}
```