> ## 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_preimage | Robinhood

> Robinhood Chain API method that returns the preimage for a given Keccak-256 hash. In Ethereum's state trie, account addresses are stored as their Keccak-256 hashes.

Robinhood Chain API method that returns the preimage for a given Keccak-256 hash. In Ethereum's state trie, account addresses are stored as their Keccak-256 hashes. This method allows retrieving the original data (preimage) that was hashed. The node must have preimage recording enabled for this method to return results.

<Note>
  Learn how to [deploy a node](/docs/debug-and-trace-apis#robinhood) 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>

<Warning>
  Preimage recording must be enabled on the node (`--cache.preimages`). If preimages are not stored, this method returns an error.
</Warning>

## Parameters

* `hash` — the Keccak-256 hash to look up the preimage for, encoded as a hex string.

## Response

* `data` — the raw preimage bytes as a hex string. Returns an error if the preimage is not found.

## `debug_preimage` code examples

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

  const provider = new JsonRpcProvider("CHAINSTACK_NODE_URL");

  async function call() {
    const result = await provider.send("debug_preimage", ["0x0000000000000000000000000000000000000000000000000000000000000000"]);
    console.log(result);
  }

  call();
  ```

  ```python web3.py theme={"system"}
  from web3 import Web3

  node_url = "CHAINSTACK_NODE_URL"
  web3 = Web3(Web3.HTTPProvider(node_url))

  result = web3.provider.make_request("debug_preimage", ["0x0000000000000000000000000000000000000000000000000000000000000000"])
  print(result)
  ```

  ```shell cURL theme={"system"}
  curl -X POST "CHAINSTACK_NODE_URL" \
    -H "Content-Type: application/json" \
    --data '{
      "jsonrpc": "2.0",
      "method": "debug_preimage",
      "params": ["0x0000000000000000000000000000000000000000000000000000000000000000"],
      "id": 1
    }'
  ```
</CodeGroup>


## OpenAPI

````yaml openapi/robinhood_node_api/debug_and_trace/debug_preimage.json POST /
openapi: 3.0.0
info:
  title: Chainstack Node API
  version: 1.0.0
  description: This is an API for interacting with a Chainstack node.
servers:
  - url: >-
      https://robinhood-mainnet.core.chainstack.com/23cf4479b299ab4835d76c05c468ca6e
security: []
paths:
  /:
    post:
      tags:
        - upload
      summary: debug_preimage
      operationId: debug_preimage
      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_preimage
                params:
                  type: array
                  items:
                    type: string
                    title: Hash
                    description: The Keccak-256 hash to look up the preimage for.
                  default:
                    - >-
                      0x0000000000000000000000000000000000000000000000000000000000000000
      responses:
        '200':
          description: Returns the preimage for the given hash.
          content:
            application/json:
              schema:
                type: object
                properties:
                  jsonrpc:
                    type: string
                  id:
                    type: integer
                  result:
                    type: string

````