eth_getStorageAt - Base

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

The eth_getStorageAt method returns the value from a storage position at a given address. This is useful for reading raw contract storage slots, which is essential for analyzing contract state and proxy implementations.

Parameters

Parameter	Type	Required	Description
address	string	Yes	20-byte address of the contract
position	string	Yes	Storage position (hex)
blockParameter	string	Yes	Block number in hex, or "latest", "earliest", "pending"

Request

cURL

curl --location --request POST 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "eth_getStorageAt",
    "params": ["0x4200000000000000000000000000000000000006", "0x0", "latest"],
    "id": "getblock.io"
}'

Axios

const axios = require('axios');

const response = await axios.post('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/', {
    jsonrpc: '2.0',
    method: 'eth_getStorageAt',
    params: [
        '0x4200000000000000000000000000000000000006',
        '0x0',
        'latest'
    ],
    id: 'getblock.io'
}, {
    headers: { 'Content-Type': 'application/json' }
});

console.log('Storage Value:', response.data.result);

Request

import requests

response = requests.post(
    'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'eth_getStorageAt',
        'params': [
            '0x4200000000000000000000000000000000000006',
            '0x0',
            'latest'
        ],
        'id': 'getblock.io'
    }
)

result = response.json()
print(f'Storage Value: {result["result"]}')

Rust

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.eu-central-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&json!({
            "jsonrpc": "2.0",
            "method": "eth_getStorageAt",
            "params": [
                "0x4200000000000000000000000000000000000006",
                "0x0",
                "latest"
            ],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;
    
    println!("Storage Value: {}", response["result"]);
    Ok(())
}

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0x0000000000000000000000000000000000000000000000000000000000000000"
}

Response Parameters

Parameter	Type	Description
jsonrpc	string	JSON-RPC protocol version ("2.0")
id	string	Request identifier matching the request
result	string	32-byte value at the storage position (hex)

Use Cases

• Proxy Detection: Read implementation address from proxy contracts

• Contract Analysis: Inspect raw contract state

• Token Analysis: Read token supply and holder data

• Governance: Check voting power and delegation

• Security Auditing: Verify contract storage layout

Error Handling

Error Code	Message	Description
-32602	Invalid params	Invalid address or position format
-32603	Internal error	Node internal failure

Web3 Integration

Ethers.js

const { ethers } = require('ethers');

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

async function getStorageAt(address, slot) {
    const value = await provider.getStorage(address, slot);
    console.log('Storage Value:', value);
    return value;
}

// Read slot 0
getStorageAt('0x4200000000000000000000000000000000000006', 0);

// Read EIP-1967 implementation slot (for proxy contracts)
async function getProxyImplementation(proxyAddress) {
    // EIP-1967 implementation slot
    const implSlot = '0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc';
    const value = await provider.getStorage(proxyAddress, implSlot);
    const implAddress = '0x' + value.slice(26); // Extract address from 32-byte value
    console.log('Implementation:', implAddress);
    return implAddress;
}

// Calculate storage slot for mapping
function getMappingSlot(mappingSlot, key) {
    const paddedKey = ethers.zeroPadValue(key, 32);
    const paddedSlot = ethers.zeroPadValue(ethers.toBeHex(mappingSlot), 32);
    return ethers.keccak256(paddedKey + paddedSlot.slice(2));
}

Second Tab

import { createPublicClient, http, keccak256, pad, toHex, concat } from 'viem';
import { base } from 'viem/chains';

const client = createPublicClient({
    chain: base,
    transport: http('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/')
});

async function getStorageAt(address, slot) {
    const value = await client.getStorageAt({
        address: address,
        slot: toHex(slot, { size: 32 })
    });
    
    console.log('Storage Value:', value);
    return value;
}

// Read slot 0
getStorageAt('0x4200000000000000000000000000000000000006', 0n);

// Read EIP-1967 implementation slot
async function getProxyImplementation(proxyAddress) {
    const implSlot = '0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc';
    const value = await client.getStorageAt({
        address: proxyAddress,
        slot: implSlot
    });
    
    const implAddress = '0x' + value.slice(26);
    console.log('Implementation:', implAddress);
    return implAddress;
}