eth_newFilter | Fantom

Fantom API method that generates a filter object based on the filter parameters. It returns a filter ID, which can be used to retrieve the filter results using the eth_getFilterChanges method. By creating a filter for specific events, developers can receive notifications when those events occur and use them to trigger actions in their applications.


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  • object β€” the filter parameters:
    • fromBlock β€” (optional, default: latest) integer that specifies the starting block number from which the logs should be fetched.
    • toBlock β€” (optional, default: latest) integer that specifies the ending block number until which the logs should be fetched.
    • address β€” (optional) the contract address from which the logs should be fetched. It can be a single address or an array of addresses.
    • topics β€” (optional) an array of DATA topics. The event topics for which the logs should be fetched. It can be a single topic or an array of topics.
    • blockhash β€” (optional) the hash of the specific block. Limits logs to a specific block with a 32-byte hash value. It takes precedence over fromBlock and toBlock.


Possible tags for fromBlock and toBlock

  • latest β€” the most recent block in the blockchain and the current state of the blockchain at the most recent block.
  • safe β€” the block that received justification from the beacon chain. Although this block could be involved in a chain reorganization, it would necessitate either a coordinated attack by the majority of validators or an instance of severe propagation latency.
  • finalized β€” the block accepted as canonical by more than 2/3 of the validators. A chain reorganization is extremely unlikely, and it would require at least 1/3 of the staked ETH to be burned.
  • earliest β€” the earliest available or genesis block.
  • pending β€” the pending state and transactions block. The current state of transactions that have been broadcast to the network but have not yet been included in a block.

See the default block parameter and How The Merge Impacts Ethereum’s Application Layer.


  • result β€” a hexadecimal string representing the ID of the newly created filter


The filters created are stored on the blockchain client instance. The filter is automatically deleted if not polled within a certain time (5 minutes by default).

Use the following methods with the filter ID:

eth_newFilter code examples


Note that the web3.eth.filter methods have been deprecated and replaced with the web3.eth.subscribe in web3.js. See web3.js subscriptions.

const ethers = require('ethers');
const provider = new ethers.JsonRpcProvider(NODE_URL);

const filter = {
  toBlock: 'latest',
  address: '0x21be370D5312f44cB42ce377BC9b8a0cEF1A4C83',
  topics: ['0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef']

const createFilter = async () => {
  try {
    const filterId = await provider.send('eth_newFilter', [filter]);
    console.log(filterId); // the filter ID returned by eth_newFilter
    return filterId
  } catch (error) {

from web3 import Web3  
web3 = Web3(Web3.HTTPProvider(node_url))

filter = {
    'toBlock': 'latest',
    'address': '0x21be370D5312f44cB42ce377BC9b8a0cEF1A4C83',
    'topics': ['0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef']

def create_logs_filter(filter_object):
        logs_filter = web3.eth.filter(filter_object)
        return logs_filter
    except Exception as e:

logs_filter = create_logs_filter(filter)
filter_id = logs_filter.filter_id
print(f'New filter ID: {filter_id}')

Use case

You can use eth_newFilter to create a filter for a specific action on a smart contract, for example, to monitor the transfer transactions from the Wrapped BNB token.

The idea is to create a filter using the eth_newFilter method to monitor an ERC-20 smart contract, WBNB in this case.

Try the eth_newFilter RPC method yourself

Click Try It! to start a request and see the response here!