> For the complete documentation index, see [llms.txt](https://docs.crypitor.com/crypitor-service/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.crypitor.com/crypitor-service/how-to-use/erc721-transfer-event.md).

# Erc721 Transfer Event

When an ERC721 NFT event occurs, Crypitor sends a JSON payload to your webhook endpoint. Below is an example of such a payload and an explanation of its structure:

**Example Payload:**

```json
{
  "chain": "POLYGON",
  "monitorId": "mo_I23ghOScgZ9xLXhV",
  "hash": "0x44ca44cca1975d6918518bd4d2d484f50c7d45e7ed4c37a9695417033bb48ac4",
  "blockNum": 56955885,
  "contract": {
    "address": "0x8751de7f7dbb9708873a4cfbad5121fc3aad7856",
    "name": null,
    "symbol": null
  },
  "fromAddress": "0x0000000000000000000000000000000000000000",
  "toAddress": "0x49f43316370482ef3aa117c168845519ad4c5e84",
  "tokenId": "281",
  "rawLog": {
    "topics": [
      "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
      "0x0000000000000000000000000000000000000000000000000000000000000000",
      "0x00000000000000000000000049f43316370482ef3aa117c168845519ad4c5e84",
      "0x0000000000000000000000000000000000000000000000000000000000000119"
    ],
    "data": "0x"
  },
  "type": "in",
  "confirm": false,
  "category": "ERC721",
  "dateCreated": "2024-05-14T10:41:02.424Z",
  "logIndex": 302,
  "txnIndex": 63,
  "associatedAddress": "0x49f43316370482ef3aa117c168845519ad4c5e84",
  "eventId": "5169d4e4ee9467f861a160f38da17805",
  "tags": [
    "polygon"
  ]
}

```

#### Data Explanation

* **chain:** The blockchain network where the event occurred (e.g., POLYGON).
* **monitorId:** Unique identifier for the monitor that captured the event.
* **hash:** Transaction hash associated with the event.
* **blockNum:** Block number in which the transaction was included.
* **contract:** Contains details about the NFT contract.
  * **address:** NFT contract address.
  * **name:** NFT contract name (null if not available).
  * **symbol:** NFT contract symbol (null if not available).
* **fromAddress:** Address from which the NFT was transferred. A zero address (`0x0000000000000000000000000000000000000000`) typically indicates a minting event.
* **toAddress:** Address to which the NFT was transferred.
* **tokenId:** Unique identifier for the NFT within the contract.
* **rawLog:** Raw log data from the blockchain.
  * **topics:** Array of indexed log topics.
  * **data:** Hex-encoded log data (empty in this example).
* **type:** Transaction type (e.g., "in" for incoming).
* **confirm:** Boolean indicating whether the transaction is confirmed.
* **category:** Type of transfer (e.g., ERC721 for NFT transfers).
* **dateCreated:** Timestamp of when the event was detected.
* **logIndex:** Position of the log in the block.
* **txnIndex:** Position of the transaction in the block.
* **associatedAddress:** Wallet address associated with the event.
* **eventId:** Unique identifier for the event.
* **tags:** Tags associated with the monitor.

####