web3_sha3 - GIWA

Example code for the web3_sha3 JSON-RPC method. Complete guide on how to use web3_sha3 JSON-RPC in GetBlock Web3 documentation.

This method returns the Keccak-256 (SHA3) hash of the given hex-encoded data. It is used to compute function selectors and event topic hashes without a local crypto library.

Parameters

Parameter	Type	Required	Description
data	string	Yes	Hex-encoded data to hash (0x-prefixed)

Request

cURL

curl --location --request POST 'https://shared.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "web3_sha3",
    "params": ["0x68656c6c6f20776f726c64"],
    "id": "getblock.io"
}'

Axios

example.js

const axios = require('axios');

const response = await axios.post('https://shared.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/', {
    jsonrpc: '2.0',
    method: 'web3_sha3',
    params: ['0x68656c6c6f20776f726c64'],
    id: 'getblock.io'
}, {
    headers: { 'Content-Type': 'application/json' }
});

console.log(response.data.result);

Request

example.py

import requests

response = requests.post(
    'https://shared.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'web3_sha3',
        'params': ['0x68656c6c6f20776f726c64'],
        '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.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&json!({
            "jsonrpc": "2.0",
            "method": "web3_sha3",
            "params": ["0x68656c6c6f20776f726c64"],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;

    println!("Result: {}", response["result"]);
    Ok(())
}

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0x47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad"
}

Response Parameters

Parameter	Type	Description
jsonrpc	string	JSON-RPC protocol version ("2.0")
id	string	Request identifier matching the request
result	string	32-byte Keccak-256 hash of the input data

Use Cases

• Function Selectors: Derive the 4-byte selector of a Solidity function signature

• Event Topics: Compute the topic0 hash for an event signature used in log filters

• Data Integrity: Hash arbitrary calldata to verify it matches an expected digest

• Off-Chain Parity: Cross-check a locally computed Keccak-256 hash against the node

Error Handling

Error Code	Message	Description
-32602	Invalid params	Input is not valid 0x-prefixed hex data
-32603	Internal error	The node failed to compute the hash

Web3 Integration

Ethers.js

ethers-example.js

import { ethers } from 'ethers';

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

const hash = ethers.keccak256(ethers.toUtf8Bytes('hello world'));

Viem

viem-example.js

import { createPublicClient, http } from 'viem';

const client = createPublicClient({
  transport: http('https://shared.ap-southeast-1.getblock.io/<ACCESS-TOKEN>/')
});

import { keccak256, toHex } from 'viem';
const hash = keccak256(toHex('hello world'));