eth_newBlockFilter-Ethereum

The eth_newBlockFilter method is part of the Ethereum JSON RPC API and is used to create a filter in the node that notifies when a new block is added to the blockchain.

Creates a filter in the node, to notify when a new block arrives. Tocheck if the state has changed, call eth_getFilterChanges.

The eth_newBlockFilter method is part of the Ethereum JSON RPC API and is used to create a filter in the node that notifies when a new block is added to the blockchain. This method is essential for monitoring block updates and is frequently utilized in Web3 applications to track real-time blockchain activity. To check for changes, the filter can be queried using the eth_getFilterChanges method.

Supported Networks

The eth_newBlockFilter RPC Ethereum method works on various Ethereum network types, including:

• Mainnet

• Testnet: Sepolia, Holesky

Parameters

This method does not require any parameters. The request can be sent with an empty parameters array.

Request

URL (API Endpoint)

https://go.getblock.io/<ACCESS-TOKEN>/

To interact with the Ethereum eth_newBlockFilter endpoint using JSON-RPC, use the following examples

JSON

curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "eth_newBlockFilter",
    "params": [],
    "id": "getblock.io"
}'

WS

wscat -c wss://eth.getblock.io/YOUR-API-KEY/ 
# wait for connection and send the request body 
{"jsonrpc": "2.0",
"method": "eth_newBlockFilter",
"params": [],
"id": "getblock.io"}

Response

The response contains the ID of the newly created filter, which can be used to query for changes.

{
    "id": "getblock.io",
    "jsonrpc": "2.0",
    "result": "0xec7fd9e32b6a15314c8d4ebfa2d3daa9"
}

Response Description

• result: A string containing the filter ID in hexadecimal format. This ID is used with the eth_getFilterChanges or eth_uninstallFilter methods.

Use Case

The value returned by the eth_newBlockFilter method, which is the filter ID, is a crucial part of real-time blockchain monitoring. Applications can use this value to retrieve updates and check for changes effectively.

The eth_newBlockFilter RPC Ethereum method is commonly used in decentralized applications (DApps) and monitoring tools to:

• Track new block arrivals in real time.

• Trigger specific actions when a block is added.

• Monitor blockchain activity for events that rely on new blocks.

For example, a Web3 application may use the Ethereum eth_newBlockFilter method to notify users of incoming transactions or to update the application state with the latest block data

Code Example

Here is an eth_newBlockFilter example of how to query the method using Python and JavaScript:

Python

import requests
import json

# Define the API URL and headers
url = 'https://go.getblock.io/<ACCESS-TOKEN>/'
headers = {'Content-Type': 'application/json'}

# Prepare the request data
data = {
    "jsonrpc": "2.0",
    "method": "eth_newBlockFilter",
    "params": [],
    "id": "getblock.io"
}

# Send the POST request
response = requests.post(url, headers=headers, data=json.dumps(data))

# Parse the JSON response
response_data = response.json()

# Print the result
print(json.dumps(response_data, indent=4))

JavaScript

const axios = require('axios');

// Define the API URL and headers
const url = 'https://go.getblock.io/<ACCESS-TOKEN>/';
const headers = { 'Content-Type': 'application/json' };

// Prepare the request data
const data = {
  jsonrpc: '2.0',
  method: 'eth_newBlockFilter',
  params: [],
  id: 'getblock.io'
};

// Send the POST request
axios.post(url, data, { headers })
  .then(response => {
    // Print the result
    console.log('Filter ID:', response.data.result);
  })
  .catch(error => {
    console.error('Error:', error);
  });

Common Errors

When using the eth_newBlockFilter RPC Ethereum method, the following issues may occur:

• Invalid URL or ACCESS-TOKEN: Ensure that the URL and token are correct and active.

• Network Connectivity Problems: Verify that the network being queried is reachable and the correct endpoint is being used.

• eth_newBlockFilter error: This error may occur if the node does not support filters or if the request is malformed.

By integrating the Web3 eth_newBlockFilter method into your application, you can monitor blockchain activity efficiently. Use this core API method to create filters and track new blocks in real time, enhancing the responsiveness of your DApp or monitoring tools.