eth_newFilter - GIWA

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

This method creates a log filter matching address and topic criteria and returns a filter ID. New matching logs are then retrieved with eth_getFilterChanges.

Parameters

Parameter	Type	Required	Description
filterObject	object	Yes	Filter criteria object

Filter Object

Field	Type	Required	Description
fromBlock	string	No	Start block in hex, or "latest"
toBlock	string	No	End block in hex, or "latest"
address	string	array	No
topics	array	No	Ordered topic filters (null matches any)

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": "eth_newFilter",
    "params": [{ "fromBlock": "0x14b8a10", "toBlock": "latest", "address": "0x4200000000000000000000000000000000000006", "topics": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"] }],
    "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: 'eth_newFilter',
    params: [{ fromBlock: '0x14b8a10', toBlock: 'latest', address: '0x4200000000000000000000000000000000000006', topics: ['0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef'] }],
    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': 'eth_newFilter',
        'params': [{ 'fromBlock': '0x14b8a10', 'toBlock': 'latest', 'address': '0x4200000000000000000000000000000000000006', 'topics': ['0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef'] }],
        '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": "eth_newFilter",
            "params": [{ "fromBlock": "0x14b8a10", "toBlock": "latest", "address": "0x4200000000000000000000000000000000000006", "topics": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"] }],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;

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

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0x1a4b0d21f8e0c3b6d2a9f7e4c1b8a5d2"
}

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

Use Cases

• Event Watching: Track ERC-20 Transfer events for a token contract

• Polling Pipelines: Create a filter, then poll changes on an interval

• Topic Filtering: Match specific event signatures by topic0

• Multi-Contract Watch: Watch several addresses with one filter

Error Handling

Error Code	Message	Description
-32602	Invalid params	Malformed filter object or topic list
-32603	Internal error	The node failed to register the filter

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>/');

// ethers v6 uses provider.on(filter, cb) rather than raw filter IDs
provider.on({ address: '0x4200000000000000000000000000000000000006', topics: ['0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef'] }, (log) => console.log(log));

Viem

viem-example.js

import { createPublicClient, http } from 'viem';

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

const filter = await client.createEventFilter({ address: '0x4200000000000000000000000000000000000006' });