eth_newFilter

Creates a filter object on Ethereum to notify when state changes (logs).

Use Cases

• Event monitoring - Subscribe to contract events
• Real-time updates - Track events for DeFi protocols (60% market share), NFT marketplaces, DAOs, and enterprise dApps
• Indexing - Build event indexes incrementally

Parameters

Parameter	Type	Required	Description
fromBlock	QUANTITY|TAG	No	Starting block
toBlock	QUANTITY|TAG	No	Ending block
address	DATA|Array	No	Contract address(es)
topics	Array	No	Topic filters

Request

{
  "jsonrpc": "2.0",
  "method": "eth_newFilter",
  "params": [{
    "fromBlock": "latest",
    "address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "topics": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"]
  }],
  "id": 1
}

Returns

Type	Description
QUANTITY	Filter ID

Code Examples

cURL

curl -X POST https://api-ethereum-mainnet.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_newFilter",
    "params": [{
      "fromBlock": "latest",
      "address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
    }],
    "id": 1
  }'

JavaScript

import { JsonRpcProvider } from 'ethers';

const provider = new JsonRpcProvider('https://api-ethereum-mainnet.n.dwellir.com/YOUR_API_KEY');

// Create filter
const filterId = await provider.send('eth_newFilter', [{
  fromBlock: 'latest',
  address: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
  topics: ['0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef']
}]);

// Poll for changes
const changes = await provider.send('eth_getFilterChanges', [filterId]);
console.log('New events:', changes);

// Cleanup
await provider.send('eth_uninstallFilter', [filterId]);

Related Methods

• eth_getFilterChanges - Poll filter for changes
• eth_uninstallFilter - Remove filter
• eth_getLogs - Direct log query