> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chainstack.com/llms.txt
> Use this file to discover all available pages before exploring further.

# eth_newBlockFilter | BNB Chain

> BNB API method that creates a filter that watches for new blocks on the blockchain. eth_newBlockFilter on BNB Chain via Chainstack.

BNB API method that creates a filter that watches for new blocks on the blockchain. It returns a filter ID, which can be used to retrieve the results using the [eth\_getFilterChanges](/reference/bnb-getfilterchanges) method. The `eth_newBlockFilter` method is useful for developers who must be notified of new blocks on the blockchain in real-time.

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## Parameters

* `none`

## Response

* `result` — a hexadecimal string representing the ID of the newly created filter.

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

Use the following methods with the filter ID:

* [eth\_getFilterChanges](/reference/bnb-getfilterchanges) to retrieve updates
* [eth\_uninstallFilter](/reference/bnb-uninstallfilter) to remove the filter

## `eth_newBlockFilter` code examples

<Note>
  **web3.eth.filterdeprecation**

  Note that the `web3.eth.filter` methods have been deprecated and replaced with the `web3.eth.subscribe` in web3.js. See [web3.js subscriptions](/reference/ethereum-web3js-subscriptions-methods).
</Note>

<CodeGroup>
  ```javascript ethers.js theme={"system"}
  const ethers = require('ethers');
  const NODE_URL = "CHAINSTACK_NODE_URL";
  const provider = new ethers.JsonRpcProvider(NODE_URL);

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

  createFilter();
  ```

  ```python web3.py theme={"system"}
  from web3 import Web3  
  node_url = "CHAINSTACK_NODE_URL" 
  web3 = Web3(Web3.HTTPProvider(node_url))

  def get_new_blocks():
      try:
          blocks_filter = web3.eth.filter('latest')
          return blocks_filter
      except Exception as e:
          print(e)

  blocks = get_new_blocks()
  filter_id = blocks.filter_id
  print(filter_id)
  ```
</CodeGroup>

## Use case

One use case for `eth_newBlockFilter` in a simple DApp is to listen for new blocks and update the user interface with the latest block information.

When the DApp starts, it creates a new filter using `eth_newBlockFilter` to listen for new blocks. When a new block is added to the blockchain, the filter is triggered, and the DApp retrieves the latest block information using a Web3 library.


## OpenAPI

````yaml /openapi/bnb_node_api/eth_newBlockFilter.json POST /35848e183f3e3303c8cfeacbea831cab
openapi: 3.0.0
info:
  title: BNB Node API
  version: 1.0.0
  description: This is an API for interacting with an BNB node.
servers:
  - url: https://bsc-mainnet.core.chainstack.com
security: []
paths:
  /35848e183f3e3303c8cfeacbea831cab:
    post:
      summary: eth_newBlockFilter
      operationId: newBlockFilter
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                jsonrpc:
                  type: string
                  default: '2.0'
                method:
                  type: string
                  default: eth_newBlockFilter
                params:
                  type: array
                  default: []
                id:
                  type: integer
                  default: 1
      responses:
        '200':
          description: The new filter ID.
          content:
            application/json:
              schema:
                type: object
                properties:
                  jsonrpc:
                    type: string
                  id:
                    type: integer
                  result:
                    type: array
                    items:
                      type: string

````