# Data Models

These are the data models you will encounter throughout Ark Core and their representations as returned in the core-api.

Keep in mind that the data structures are kept consistent as much as possible for the sake of backward and forwards compatibility. As such, these data hierarchies are not necessarily the same as the object's internal representation.

This is something to keep in mind when accessing these models through the Event API, for example, as the correct way to obtain information might be different from following the structure listed here.

Where possible, these discrepancies are noted below. The transformers directories in the core-api module help to paint a complete picture; they can be found in their respective v1 and v2 repositories.

# Block

Blocks are the core unit of any given blockchain. In ARK, blocks contain a group of transactions and are signed by a delegate to validate their authenticity.

• id
• version the version of ARK active on the network when the block was forged
• height the height of the block
• previous the ID of the previous block in the chain
• forged:
  • reward total reward for mining block
  • fee total fee paid by users for this block
  • total total reward + total fee
• payload fields holding metadata on the block's transactions:
  • hash The SHA256 hash of the block's content
  • length the length of the payload hash in bytes
• generator the delegate who generated the block:
  • username
  • address
  • publicKey
• signature the signature of the delegate who forged the block
• confirmations the amount of times the network has declared this block as valid
• transactions the amount of transactions in the block
• timestamp

# Transaction

Transactions are the heart of any blockchain, cryptocurrency or otherwise. They represent a transfer of value from one network participant to another. In ARK, transactions can be of one of multiple types, specified in AIP11, which can affect the content and data structure of each transaction's payload.

• id
• blockId the ID of the block in which this transaction is included
• type the AIP11 type of the transaction
• amount the transaction value in arktoshis
• fee the fee paid to include the transaction in its block
• sender the address of the transaction sender
• recipient the address of the transaction recipient
• signature the signature of the sending party
• signSignature if secondSignature is enabled, the second signature is stored here
• signatures an array of the transaction's signatures, used in multisignature transactions to validate more than two signatures
• vendorField an optional text field written by the sender and associated with the transaction
• asset the type-specific transaction payload
• confirmations the amount of times this transaction's block has been confirmed
• timestamp

# Wallet

Wallets are individual accounts on the ARK ledger. Each wallet has a balance that grows and shrinks as the wallet sends and receives transactions on the network. Additionally, each wallet can cast exactly one vote for one delegate to forge on their behalf.

Note in particular that private keys and passphrases are not included on this model, as they are never stored in memory at any point during the operation of Ark Core nodes.

• address the wallet's address, derived from public key
• publicKey the wallet's public key, derived from private key
• secondPublicKey if the wallet has enabled a second key, that second key is stored here
• vote the delegate username of this wallet's vote recipient

# Delegate

Though delegates are treated as their own data type in the ARK Public API, in their implementation delegates are nothing more than wallets whose owners have registered a delegate username.

They share all fields in common with the Wallet data structure, with a few extra fields:

• username the delegate username of this wallet
• voteBalance the sum of balances of all wallets voting for the delegate
• producedBlocks the total number of blocks produced by the delegate
• missedBlocks the total number of blocks missed by the delegate

# Peer

Peers are nodes in the Ark network that work together to relay transactions and form consent. Each node keeps a list of current peers, regularly pruning and updating the list as new peers join and leave the network.

• ip the IP address of the peer
• port the port on which the peer has enabled its P2P connection
• version the network version this peer is operating on
• height the total height of the blockchain as reported by the peer
• status the operational status of the peer
• os the operating system running on the peer
• latency the average delay between contacting the peer and receiving a response