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://go.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

Request

Rust

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://go.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));
}

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