eth_newFilter - Optimism

Example code for the eth_newFilter json-rpc method. Сomplete guide on how to use eth_newFilter json-rpc in GetBlock.io Web3 documentation.

This method creates a filter that can be polled for new log events matching the specified criteria. The filter can be configured with address, topic, and block-range parameters. Once created, use eth_getFilterChanges to retrieve new logs that match the filter. Filters timeout if not polled regularly.

Parameters

Parameter	Type	Description	Required
filterObject	Object	Filter object with optional fromBlock, toBlock, address, and topics fields.	Yes

Request sample

Request

cURL

curl --location 'https://shared.us-east-1.getblock.io/<ACCESS_TOKEN>' \
--header 'Content-Type: application/json' \
--data '{
   "jsonrpc": "2.0",
    "method": "eth_newFilter",
    "params": [
        {
            "fromBlock": "latest",
            "address": "0x4200000000000000000000000000000000000006",
            "topics": [
                "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
            ]
        }
    ],
    "id": "getblock.io"
}'

Axios

import axios from 'axios'
let data = JSON.stringify({
    "jsonrpc": "2.0",
       "method": "eth_newFilter",
    "params": [
        {
            "fromBlock": "latest",
            "address": "0x4200000000000000000000000000000000000006",
            "topics": [
                "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
            ]
        }
    ],
    "id": "getblock.io"
};

let config = {
  method: "post",
  maxBodyLength: Infinity,
  url: "https://shared.us-east-1.getblock.io/<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);
  });

Request

import requests
import json

url = "https://shared.us-east-1.getblock.io/<ACESS_TOKEN>"

payload = json.dumps({
   "jsonrpc": "2.0",
    "method": "eth_newFilter",
    "param":[
        {
            "fromBlock": "latest",
            "address": "0x4200000000000000000000000000000000000006",
            "topics": [
                "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
            ]
        }
    ],        }]
    "id": "getblock.io"
})
headers = {
  'Content-Type': 'application/json'
}

response = requests.request("POST", url, headers=headers, data=payload)

print(response.text)

Rust

#[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_newFilter",
    "params": [
        {
            "fromBlock": "latest",
            "address": "0x4200000000000000000000000000000000000006",
            "topics": [
                "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
            ]
        }
    ],
    "id": "getblock.io"
}"#;

    let json: serde_json::Value = serde_json::from_str(&data)?;

    let request = client.request(reqwest::Method::POST, "https://shared.us-east-1.getblock.io/<ACCESS_TOKEN>")
        .headers(headers)
        .json(&json);

    let response = request.send().await?;
    let body = response.text().await?;

    println!("{}", body);

    Ok(())
}

Response

A successful response returns the following:

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0xfd9d8fda4aa66371b08ac6366a0fa171"
}

Response Parameters

• id: A unique request identifier, matching the id sent in the request body.

• jsonrpc: Specifies the use of JSON-RPC version 2.0.

• result: A filter ID that can be used with eth_getFilterChanges and eth_uninstallFilter.

Use Case

The eth_newFilter method is commonly used for:

• Event monitoring

• Log polling

• Real-time event tracking

• Contract event subscription

Error handling

Status Code	Error Message	Cause
404	Not Found	Missing or invalid ACCESS_TOKEN.
-32602	Invalid argument	Invalid filter parameters Rate limit

Integration with Web3

Using eth_newFilter allows developers to:

• Build interfaces that listen for contract events without needing WebSocket support

• Implement background polling workers for analytics dashboards

• Detect state changes in dapps and update UI instantly

• Create automated bots such as liquidation bots or claim bots

• Watch ERC20, ERC721, and custom events in a trustless way

Ethers.js

import { ethers } from "ethers";
const RPC_URL = "https://shared.us-east-1.getblock.io/<ACCESS_TOKEN>";
const provider = new ethers.JsonRpcProvider(RPC_URL);
async function Call() {
  try {
     const result = await provider.send( "eth_newFilter",[
        {
            "fromBlock": "latest",
            "address": "0x4200000000000000000000000000000000000006",
            "topics": [
                "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
            ]
        }
    ]);    
console.log("The result:", result);
    return result;
  } catch (error) {
    console.error("The error:", error);
    throw error;
  }
}

Viem

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

// Create Viem client with GetBlock
const client = createPublicClient({
  chain: optimism,
  transport: http('https://shared.us-east-1.getblock.io/<ACCESS_TOKEN>'
});

// Using the method through Viem
async function Call() {
    try {
        // Method-specific Viem implementation
        const result = await client.request({
          method: "eth_newFilter",
    "params": [
        {
            "fromBlock": "latest",
            "address": "0x4200000000000000000000000000000000000006",
            "topics": [
                "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
            ]
        }
    ],
        });
        console.log('Result:', result);
        return result;
    } catch (error) {
        console.error('Viem Error:', error);
        throw error;
    }
}