🚧
Deprecation notice
Webhooks v1 will be deprecated on June 15th, 2026. Please use the Developer Center in the Fireblocks Console to upgrade to Webhooks V2, which offers improved reliability, performance, and observability.

This page describes all events related to reporting balance changes for incoming and outgoing non-fungible token (NFT) transfers that produce webhook notifications and their associated data objects.

Webhook payload

type: string, // NFT_BALANCE_CHANGED
tenantId: string,
timestamp: number,
data: {
  id: string, // unique web-hook id
  transaction?: TransactionObject, // when WH is from refresh call, this will be empty
  token: TokenObject,
  balance: BalanceObject, // current balance
}

Data Objects

TransactionObject

Name	Type	Description
id	string	The Fireblocks transaction ID.
hash	string	The hash of the transaction for the on-chain NFT transfer.
blockNumber	number	The transaction's block number.

TokenObject

Name	Type	Description
assetId	string	The identifier of the NFT asset.
blockchainDescriptor	string	The descriptor for the specific blockchain network.
tokenId	string	The ID of the transferred token.
contractAddress	string [Optional]	The address of the NFT contract.
standard	string [Optional]	The NFT standard for the token.

BalanceObject

Name	Type	Description
owner	OwnerObject	The owner of the NFT with the changed balance.
outgoing	boolean [Optional]	Indicates whether the transfer is outgoing from the vault.
amount	string [Optional]	The amount of the NFT transferred in the balance change.
total	string	The token balance. Represented as a decimal string.
blockNumber	number	The block number of the NFT when its token balance was last queried.

OwnerObject

Name	Type	Description
type	PeerType	The source of the transfer (e.g., VAULT_ACCOUNT, INTERNAL_WALLET).
accountId	string	The vault account ID.
walletId	string [Optional]	The Non-Custodial Wallet (NCW) ID.
address	string	The owner's wallet address (i.e., the vault account ID or the NCW ID).