> ## 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.

# debug_getModifiedAccountsByNumber | Arbitrum

> Arbitrum API method that retrieves a list of accounts that were modified in a specific block or between two blocks, identified by block number.

Arbitrum API method that retrieves a list of accounts that were modified in a specific block or between two blocks, identified by block number. This method compares the state tries between the specified blocks to find all accounts with changed state.

<Note>
  Learn how to [deploy a node](/docs/debug-and-trace-apis#arbitrum) with the debug and trace API methods enabled.
</Note>

<Warning>
  This method is available for post-Nitro blocks only (block 22,207,815 and later). For pre-Nitro blocks, use the `arbtrace_*` methods instead.
</Warning>

<Check>
  **Get your own node endpoint today**

  [Start for free](https://console.chainstack.com/) and get your app to production levels immediately. No credit card required.

  You can sign up with your GitHub, X, Google, or Microsoft account.
</Check>

## Parameters

* `startNum` — the block number (as a decimal integer) for which to retrieve modified accounts. When only this parameter is provided, the method returns accounts modified in this single block (compared to its parent).
* `endNum` — (optional) the end block number (as a decimal integer). When provided, the method returns accounts modified between `startNum` and `endNum`.

## Response

* `result` — an array of account addresses that were modified in the specified block or range.

## `debug_getModifiedAccountsByNumber` code examples

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

  const getModifiedAccounts = async (startBlock, endBlock) => {
    const result = await provider.send("debug_getModifiedAccountsByNumber", [startBlock, endBlock]);
    console.log(result);
  };

  // Get accounts modified in a single block
  getModifiedAccounts(30000000);
  ```

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

  # Get accounts modified in a single block
  result = web3.provider.make_request('debug_getModifiedAccountsByNumber', [30000000])
  print(result)
  ```
</CodeGroup>

## Use case

The `debug_getModifiedAccountsByNumber` method is useful for monitoring state changes over a range of blocks. Developers can use it to build state diff tools, track which accounts are affected by a series of transactions, or perform forensic analysis on state changes across a block range. Unlike `debug_getModifiedAccountsByHash`, this method accepts block numbers, making it more convenient for iterating over sequential blocks.


## OpenAPI

````yaml /openapi/arbitrum_node_api/debug_and_trace/debug_getModifiedAccountsByNumber.json POST /66f812de2a6724a75a51f60dd6f2a154
openapi: 3.0.0
info:
  title: Chainstack Node API
  version: 1.0.6
  description: >-
    This is an API for interacting with a Chainstack node using the
    debug_getModifiedAccountsByNumber method.
servers:
  - url: https://nd-954-882-037.p2pify.com
security: []
paths:
  /66f812de2a6724a75a51f60dd6f2a154:
    post:
      tags:
        - upload
      summary: debug_getModifiedAccountsByNumber
      operationId: debugGetModifiedAccountsByNumber
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                id:
                  type: integer
                  default: 1
                jsonrpc:
                  type: string
                  default: '2.0'
                method:
                  type: string
                  default: debug_getModifiedAccountsByNumber
                params:
                  type: array
                  items:
                    type: integer
                  default:
                    - 30000000
      responses:
        '200':
          description: Returns a list of accounts modified between the specified blocks.
          content:
            application/json:
              schema:
                type: object
                properties:
                  jsonrpc:
                    type: string
                  id:
                    type: integer
                  result:
                    type: array
                    items:
                      type: string
                    description: The addresses of the modified accounts.

````