eth_newBlockFilter - Ethereum

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

This method creates a filter that fires each time a new block is added to the chain. Returns a filter ID that subsequent eth_getFilterChanges calls poll to receive block hashes. Lighter-weight than log filters — no criteria, just chain-tip advancement notifications.

Parameters

This method takes no parameters.

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_newBlockFilter",
    "params": [],
    "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_newBlockFilter',
    params: [],
    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_newBlockFilter',
        'params': [],
        '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_newBlockFilter",
            "params": [],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;
    
    println!("Result: {}", response["result"]);
    Ok(())
}

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0x1a"
}

Response Parameters

Parameter	Type	Description
jsonrpc	string	JSON-RPC protocol version ("2.0")
id	string	Request identifier matching the request
result	string	Hex-encoded filter ID — pass to eth_getFilterChanges to receive new block hashes

Use Cases

• New Block Notifications: Poll to receive block hashes for each newly produced block without subscribing over WSS

• Simple Chain-Progress Indicators: Feed a UI 'live block' badge without full block details

• Trigger Periodic Work: Kick off backend work (indexer runs, reorg checks) once per new block

Error Handling

Error Code	Message	Description
-32603	Internal error	Node failed to create the filter

Web3 Integration

Ethers.js

ethers-example.js

import { ethers } from 'ethers';

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

const filterId = await provider.send('eth_newBlockFilter', []);
console.log('Block filter ID:', filterId);

setInterval(async () => {
    const hashes = await provider.send('eth_getFilterChanges', [filterId]);
    hashes.forEach(h => console.log('New block:', h));
}, 12000);

Viem

viem-example.js

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

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

const filter = await client.createBlockFilter();
console.log('Block filter ID:', filter.id);

setInterval(async () => {
    const hashes = await client.getFilterChanges({ filter });
    hashes.forEach(h => console.log('New block:', h));
}, 12000);