eth_getStorageAt - Flashblocks

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

This returns the value stored at a specific storage slot of a contract. When called with "pending", reflects storage changes from every transaction preconfirmed into the latest Flashblock — letting applications read intermediate contract state before block seal.

Parameters

Parameter	Type	Required	Description
address	DATA (20 bytes)	Yes	Contract address
slot	QUANTITY	Yes	Storage slot index (hex)
block	QUANTITY	TAG	Yes

Request Example

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": [
        "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "0x0",
        "pending"
    ],
    "id": "getblock.io"
}'

JavaScript (Axios)

import axios from 'axios';

const data = JSON.stringify({
    "jsonrpc": "2.0",
    "method": "eth_getStorageAt",
    "params": [
        "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "0x0",
        "pending"
    ],
    "id": "getblock.io"
});

const config = {
    method: 'post',
    url: 'https://go.getblock.io/<ACCESS-TOKEN>/',
    headers: {
        'Content-Type': 'application/json'
    },
    data: data
};

axios(config)
    .then(response => console.log(JSON.stringify(response.data, null, 2)))
    .catch(error => console.log(error));

Python (Requests)

import requests
import json

url = "https://go.getblock.io/<ACCESS-TOKEN>/"

payload = json.dumps({
    "jsonrpc": "2.0",
    "method": "eth_getStorageAt",
    "params": [
        "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "0x0",
        "pending"
    ],
    "id": "getblock.io"
})

headers = {
    'Content-Type': 'application/json'
}

response = requests.post(url, headers=headers, data=payload)
print(response.text)

Rust (Reqwest)

use reqwest::Client;
use serde_json::json;

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

    let payload = json!({
        "jsonrpc": "2.0",
        "method": "eth_getStorageAt",
        "params": [
                "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
                "0x0",
                "pending"
        ],
        "id": "getblock.io"
});

    let response = client
        .post("https://go.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&payload)
        .send()
        .await?;

    let result: serde_json::Value = response.json().await?;
    println!("{:#?}", result);

    Ok(())
}

Response Example

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0x0000000000000000000000000000000000000000000000000000000000000064"
}

Response Parameters

Field	Type	Description
result	DATA (32 bytes)	Value at the storage slot, reflecting preconfirmed state

Use Cases

• Reading contract state that has been updated by preconfirmed transactions

• Monitoring internal state changes in real-time (e.g. AMM reserves, oracle prices)

• Auditing tools that need to-the-Flashblock state visibility

Error Handling

Status Code	Error Message	Cause
403	Forbidden	Missing or invalid <ACCESS-TOKEN>
-32602	Invalid params	Request parameters are missing or malformed
-32603	Internal error	Server-side error while processing the request
429	Too Many Requests	Rate limit exceeded for your plan

SDK Integration

ethers.js

import { ethers } from 'ethers';

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

// Generic JSON-RPC call — 'pending' returns Flashblocks-preconfirmed state:
const result = await provider.send('eth_getStorageAt', ["0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913", "0x0", "pending"]);
console.log(result);

// Many standard methods have typed wrappers on ethers Provider that accept 'pending':
// provider.getBalance(addr, 'pending'), provider.getTransactionCount(addr, 'pending'), etc.

viem

import { createPublicClient, http } from 'viem';

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

// viem's read methods accept blockTag: 'pending' for Flashblocks-preconfirmed state:
const result = await client.request({
    method: 'eth_getStorageAt',
    params: ["0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913", "0x0", "pending"]
});
console.log(result);

// Typed wrappers also accept blockTag: 'pending':
// client.getBalance({ address, blockTag: 'pending' })
// client.getBlock({ blockTag: 'pending' })