eth_call - Unichain

Example code for the eth_call JSON-RPC method. Complete guide to using the eth_call JSON-RPC method in the GetBlock.io Web3 documentation.

This method executes a new message call immediately without creating a transaction on the blockchain. This is the primary method for reading data from smart contracts, including token balances, contract state, and view or pure function results.

Parameters

Parameter	Type	Required	Description
transaction	object	Yes	Transaction call object
blockParameter	string	Yes	Block number in hex, or "latest", "earliest", "pending"

Transaction Object

Field	Type	Required	Description
from	string	No	20-byte sender address
to	string	Yes	20-byte recipient or contract address
gas	string	No	Gas limit for the call (hex)
gasPrice	string	No	Gas price in wei (hex)
value	string	No	Value to send in wei (hex)
data	string	No	Encoded function call data

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_call",
    "params": [{"to": "0x4200000000000000000000000000000000000006", "data": "0x70a08231000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045"}, "latest"],
    "id": "getblock.io"
}'

Axios

example.js

const axios = require('axios');

const response = await axios.post('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/', {
    jsonrpc: '2.0',
    method: 'eth_call',
    params: [{"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.eu-central-1.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'eth_call',
        'params': [{"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.eu-central-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&json!({
            "jsonrpc": "2.0",
            "method": "eth_call",
            "params": [{"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": "0x0000000000000000000000000000000000000000000000008ac7230489e80000"
}

Response Parameters

Parameter	Type	Description
jsonrpc	string	JSON-RPC protocol version ("2.0")
id	string	Request identifier matching the request
result	string	Hex-encoded return data from the contract call

Use Cases

• Token Balances: Query ERC-20 token balances using balanceOf

• Contract State: Read public state variables from smart contracts

• Price Feeds: Query oracle prices from Chainlink or other protocols

• DeFi Calculations: Query pool reserves, exchange rates, and liquidity

• NFT Metadata: Read NFT ownership and token metadata

Error Handling

Error Code	Message	Description
-32602	Invalid params	Invalid transaction object or block parameter
-32603	Internal error	Contract execution error
3	Execution reverted	The contract reverted the call
-32000	Execution error	Insufficient gas or other execution failure

Web3 Integration

Ethers.js

ethers-example.js

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

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

const abi = ['function balanceOf(address) view returns (uint256)'];
const token = new ethers.Contract('0x4200000000000000000000000000000000000006', abi, provider);
const balance = await token.balanceOf('0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045');
console.log(ethers.formatUnits(balance, 18));

Viem

viem-example.js

import { createPublicClient, http } from 'viem';
import { unichain } from 'viem/chains';

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

const balance = await client.readContract({
    address: '0x4200000000000000000000000000000000000006',
    abi: [{ name: 'balanceOf', type: 'function', stateMutability: 'view',
            inputs: [{ name: 'account', type: 'address' }], outputs: [{ type: 'uint256' }] }],
    functionName: 'balanceOf',
    args: ['0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045']
});
console.log(balance);