eth_createAccessList - GIWA

Example code for the eth_createAccessList JSON-RPC method. Complete guide on how to use eth_createAccessList JSON-RPC in GetBlock Web3 documentation.

This method returns an EIP-2930 access list for a transaction along with the gas used, which can reduce gas costs for transactions that touch many storage slots.

Parameters

Parameter	Type	Required	Description
transaction	object	Yes	Transaction call object
blockParameter	string	No	Block number in hex, or "latest", "pending"

Transaction Object

Field	Type	Required	Description
from	string	No	20-byte sender address
to	string	Yes	20-byte recipient/contract address
data	string	No	Encoded function call data

Request

cURL

curl --location --request POST 'https://shared.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "eth_createAccessList",
    "params": [{ "from": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", "to": "0x4200000000000000000000000000000000000006", "data": "0x70a08231000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045" }, "latest"],
    "id": "getblock.io"
}'

Axios

example.js

const axios = require('axios');

const response = await axios.post('https://shared.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/', {
    jsonrpc: '2.0',
    method: 'eth_createAccessList',
    params: [{ from: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', to: '0x4200000000000000000000000000000000000006', data: '0x70a08231000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045' }, 'latest'],
    id: 'getblock.io'
}, {
    headers: { 'Content-Type': 'application/json' }
});

console.log(response.data.result);

Request

example.py

import requests

response = requests.post(
    'https://shared.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'eth_createAccessList',
        'params': [{ 'from': '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', 'to': '0x4200000000000000000000000000000000000006', 'data': '0x70a08231000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045' }, 'latest'],
        'id': 'getblock.io'
    }
)

print(response.json())

Rust

example.rs

use reqwest::Client;
use serde_json::{json, Value};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();

    let response = client
        .post("https://shared.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&json!({
            "jsonrpc": "2.0",
            "method": "eth_createAccessList",
            "params": [{ "from": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", "to": "0x4200000000000000000000000000000000000006", "data": "0x70a08231000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045" }, "latest"],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;

    println!("Result: {}", response["result"]);
    Ok(())
}

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": {
        "accessList": [
            {
                "address": "0x4200000000000000000000000000000000000006",
                "storageKeys": [
                    "0x0000000000000000000000000000000000000000000000000000000000000000"
                ]
            }
        ],
        "gasUsed": "0x64a3"
    }
}

Response Parameters

Parameter	Type	Description
jsonrpc	string	JSON-RPC protocol version ("2.0")
id	string	Request identifier matching the request
result	object	Access list plus gas used (see fields below)

Result Object

Field	Type	Description
accessList	array	Addresses and storage keys the transaction accesses
gasUsed	string	Gas used when the access list is applied (hex)

Use Cases

• Gas Optimization: Attach an access list to reduce SLOAD costs on hot slots

• Type-1 Transactions: Build EIP-2930 access-list transactions

• Simulation: Discover which storage slots a call touches

• Tooling: Feed generated access lists into transaction builders

Error Handling

Error Code	Message	Description
-32602	Invalid params	Malformed transaction object or block parameter
-32000	Execution error	The transaction failed while building the access list

Web3 Integration

Ethers.js

ethers-example.js

import { ethers } from 'ethers';

const provider = new ethers.JsonRpcProvider('https://shared.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/');

const al = await provider.send('eth_createAccessList', [{ from: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', to: '0x4200000000000000000000000000000000000006', data: '0x70a08231000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045' }, 'latest']);

Viem

viem-example.js

import { createPublicClient, http } from 'viem';

const client = createPublicClient({
  transport: http('https://shared.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/')
});

const al = await client.request({ method: 'eth_createAccessList', params: [{ from: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', to: '0x4200000000000000000000000000000000000006', data: '0x70a08231000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045' }, 'latest'] });