eth_getUncleByBlockHashAndIndex - Arbitrum

Example code for the eth_getUncleByBlockHashAndIndex JSON RPC method. Сomplete guide on how to use eth_getUncleByBlockHashAndIndex JSON RPC in GetBlock Web3 documentation.

This method returns information about an uncle block by referencing the parent block's hash and the uncle's index.

Since Arbitrum does not produce uncle blocks, this method always returns null, but it is still included for EVM compatibility.

Parameters

Parameter

Type

Required

Description

block_hash

string

yes

The hash of the block containing the uncle. Must be a 32 byte hex string starting with 0x.

uncle_index

string

yes

The index position of the uncle block. Must be a hex number, for example "0x0".

Request

curl --location 'https://go.getblock.us/<ACCESS_TOKEN>' \
--header 'Content-Type: application/json' \
--data '{
   "jsonrpc": "2.0",
  "method": "eth_getUncleByBlockHashAndIndex",
  "params": [
    "0xb3b20624f8f0f86eb50dd04688409e5cea4bd02d700bf6e79e9384d47d6a5a35",
    "0x0"
  ],
    "id": "getblock.io"
}'

import axios from 'axios'
let data = JSON.stringify({
    "jsonrpc": "2.0",
     "method": "eth_getUncleByBlockHashAndIndex",
  "params": [
    "0xb3b20624f8f0f86eb50dd04688409e5cea4bd02d700bf6e79e9384d47d6a5a35",
    "0x0"
  ],
    "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_getUncleByBlockHashAndIndex",
  "params": [
    "0xb3b20624f8f0f86eb50dd04688409e5cea4bd02d700bf6e79e9384d47d6a5a35",
    "0x0"
  ],
    "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_getUncleByBlockHashAndIndex",
  "params": [
    "0xb3b20624f8f0f86eb50dd04688409e5cea4bd02d700bf6e79e9384d47d6a5a35",
    "0x0"
  ],
    "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

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

Reponse Parameter Definition

Field

Description

number

Block number of the uncle

hash

Hash of the uncle block

parentHash

Hash of parent block

miner

Address of miner who produced the uncle

difficulty

Difficulty of the uncle block

gasLimit

Gas limit

gasUsed

Gas used

timestamp

Timestamp of the uncle block

uncles

Always empty for uncles

But again, on Arbitrum the value is always null.

Use case

Even though Arbitrum does not generate uncle blocks, developers may still call this method because it helps to:

Maintain compatibility with Ethereum-based tools, explorers, and SDKs
Avoid breaking code paths where multiple RPCs are used generically
Simplify integration with indexing libraries that expect uncle queries

Error handling

Status Code

Error Message

Cause

403

Forbidden

Missing or invalid ACCESS_TOKEN.

-32602

Invalid argument

Invalid block hash
Invalid index

Integration with Web3

The eth_getUncleByBlockHashAndIndex method helps developers to:

Maintain uniform code paths when interacting with multiple EVM networks
Ensure compatibility with Ethereum-based frameworks
Safely account for uncle data even when none exist
Support explorers, analytics platforms, and monitoring tools needing consistent RPC coverage

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_getUncleByBlockHashAndIndex", [
    "0xb3b20624f8f0f86eb50dd04688409e5cea4bd02d700bf6e79e9384d47d6a5a35",
    "0x0"
  ],);    
console.log("The result:", result);
    return result;
  } catch (error) {
    console.error("The error:", error);
    throw error;
  }
}

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

// Create Viem client with GetBlock
const client = createPublicClient({
  chain: arbitrum,
  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_getUncleByBlockHashAndIndex",
         params: [
    "0xb3b20624f8f0f86eb50dd04688409e5cea4bd02d700bf6e79e9384d47d6a5a35",
    "0x0"
  ]});
        console.log('Result:', result);
        return result;
    } catch (error) {
        console.error('Viem Error:', error);
        throw error;
    }
}

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