eth_getCode - Optimism

Example code for the eth_getCode json-rpc method. Сomplete guide on how to use eth_getCode json-rpc in GetBlock.io Web3 documentation.

This method retrieves the EVM bytecode stored at a specific address. If the address is an externally owned account (EOA) or an empty address, it returns '0x'. This is useful for verifying contract deployments, analyzing contracts, and checking whether an address is a contract or an EOA. The bytecode is the compiled version of the smart contract's source code.

Parameters

Parameter

Type

Description

Required

address

DATA, 20 Bytes

The address to retrieve bytecode from.

Yes

block

QUANTITY|TAG

Block number in hex, or 'latest', 'earliest', 'pending'.

Yes

Request

curl --location 'https://go.getblock.us/<ACCESS_TOKEN>' \
--header 'Content-Type: application/json' \
--data '{
   "jsonrpc": "2.0",
   "method": "eth_getCode",
    "params": [
        "0x4200000000000000000000000000000000000006",
        "latest"
    ],
    "id": "getblock.io"
}'

import axios from 'axios'
let data = JSON.stringify({
    "jsonrpc": "2.0",
   "method": "eth_getCode",
    "params": [
        "0x4200000000000000000000000000000000000006",
        "latest"
    ],
    "id": "getblock.io"
};

let config = {
  method: "post",
  maxBodyLength: Infinity,
  url: "https://go.getblock.us/<ACCESS_TOKEN>",
  headers: {
    "Content-Type": "application/json",
  },
  data: data,
};

axios
  .request(config)
  .then((response) => {
    console.log(JSON.stringify(response.data));
  })
  .catch((error) => {
    console.log(error);
  });

import requests
import json

url = "https://go.getblock.us/<ACESS_TOKEN>"

payload = json.dumps({
   "jsonrpc": "2.0",
    "method": "eth_getCode",
    "params": [
        "0x4200000000000000000000000000000000000006",
        "latest"
    ],
    "id": "getblock.io"
})
headers = {
  'Content-Type': 'application/json'
}

response = requests.request("POST", url, headers=headers, data=payload)

print(response.text)

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

    let mut headers = reqwest::header::HeaderMap::new();
    headers.insert("Content-Type", "application/json".parse()?);

    let data = r#"{
   "jsonrpc": "2.0",
   "method": "eth_getCode",
    "params": [
        "0x4200000000000000000000000000000000000006",
        "latest"
    ],
    "id": "getblock.io"
}"#;

    let json: serde_json::Value = serde_json::from_str(&data)?;

    let request = client.request(reqwest::Method::POST, "https://go.getblock.us/<ACCESS_TOKEN>")
        .headers(headers)
        .json(&json);

    let response = request.send().await?;
    let body = response.text().await?;

    println!("{}", body);

    Ok(())
}

Response

A successful response returns the following:

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

Response Parameters

id: A unique request identifier, matching the id sent in the request body.
jsonrpc: Specifies the use of JSON-RPC version 2.0.
result: The bytecode at the address as a hexadecimal string. Returns '0x' for EOAs or empty addresses.

Use Case

The eth_getCode method is commonly used for:

Contract verification
EOA vs contract detection
Security analysis
Bytecode comparison

Error handling

Status Code

Error Message

Cause

404

Not Found

Missing or invalid ACCESS_TOKEN.

-32602

Invalid argument

The Address not 20 bytes or missing prefix
block hash isn't accurate or incomplete
keyword missing

Integration with Web3

The eth_getCode method helps developers to:

Detect whether a user is interacting with a contract or a wallet
Validate deployed bytecode for audit and debugging purposes
Build tools that identify proxies, multicall contracts, routers, and libraries
Support trustless dapps that rely on on-chain introspection
Ensure safe interactions by verifying contract code before sending transactions

import { ethers } from "ethers";
const RPC_URL = "https://go.getblock.us/<ACCESS_TOKEN>";
const provider = new ethers.JsonRpcProvider(RPC_URL);
async function Call() {
  try {
     const result = await provider.send("eth_getCode",
  [
        "0x4200000000000000000000000000000000000006",
        "latest"
    ],);    
console.log("The result:", result);
    return result;
  } catch (error) {
    console.error("The error:", error);
    throw error;
  }
}

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

// Create Viem client with GetBlock
const client = createPublicClient({
  chain: optimism,
  transport: http('https://go.getblock.us/<ACCESS_TOKEN>'),
});

// Using the method through Viem
async function Call() {
    try {
        // Method-specific Viem implementation
        const result = await client.request({
          "method": "eth_getCode",
    "params": [
        "0x4200000000000000000000000000000000000006",
        "latest"
    ]
        });
        console.log('Result:', result);
        return result;
    } catch (error) {
        console.error('Viem Error:', error);
        throw error;
    }
}

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