1. Reading Data on VeChainThor

1.1 Setting Up the VeChain SDK

VeChain SDK provides all the tools needed to interact with VeChainThor. 

Install the SDK packages:

npm install @vechain/sdk-core
npm install @vechain/sdk-network

1.2 Connect To the Network

VeChain has two networks: mainnet (for real transactions) and testnet (for development and testing). For this tutorial, we'll connect to mainnet, since we will use AI Agents to fetch data.

import { ThorClient } from '@vechain/sdk-network';

// Connect to mainnet
const thor = ThorClient.at("https://mainnet.vechain.org");

// For testnet, use:
// const thorClient = ThorClient.fromUrl('https://testnet.vechain.org');

1.3 Reading Account Information

An account can be classified as either an externally owned account or a smart contract. 

1. Externally owned account - consists of private keys generated in wallets.

2. Smart contracts - they are deployed with specific program codes.

The difference between the two can be made by examining an account's hasCode flag. If it's true, it indicates that a smart contract is deployed at that address. For smart contracts, the bytecode can also be retrieved.

An account has three key attributes:

• hasCode - indicates a smart contract at the address

• balance - shows the VET balance

• energy - shows the VTHO balance

This is how querying Account Information looks like:

import { ThorClient } from '@vechain/sdk-network';

const thor = ThorClient.at('https://testnet.vechain.org');

const account = await thor.accounts.getAccount(
  '0x01d6b50b31c18d7f81ede43935cadf79901b0ea0'
);

console.log(account);
console.log('VET Balance', BigInt(account.balance)/1000000000000000000n );
console.log('VTHO Balance', BigInt(account.energy)/1000000000000000000n );

And here’s an example response:

j { balance: '0x0', energy: '0x0', hasCode: true }
VET Balance 1000n
VTHO Balance 500n

1.4 How To Read Transactions

Transactions are changes on the blockchain, which can be a transfer of VET or the execution of the contract’s function. 

A transaction on VeChain consists of two parts:

1. Transaction Body

2. Transaction Receipt

Reading both will give you a full understanding of the transaction.

Transaction Body

Transaction body contains:

• id - Unique transaction identifier.

• chainTag - Identifier of the Blockchain.

• blockRef - Block on which the call was made.

• expiration - The transaction must be added within this many blocks, or it will fail.

• origin -  Sender of the transaction.

• clauses - Instructions that need to be executed, including recipients, value, and data.

• meta - Block metadata (BlockID, BlockNumber, and BlockTimestamp).

This is how you query transaction information:

import { ThorClient } from '@vechain/sdk-network';
const thor = ThorClient.at('https://mainnet.vechain.org');


const tx = await thor.transactions.getTransaction(
    '0x0326f6e9dc11e2754c3618cff79fd23e7f25305626df7856551518aefd534ed9'
);
console.log(tx);

Transaction Receipt

The transaction receipt shows the outcome and blockchain changes. 

It contains:

• reverted - Indicates if the transaction failed.

• gasUsed - The amount of gas that was used to complete the transaction.

• outputs - Events that have been triggered as a result of the transaction.

• contractAddress - Address of a newly deployed contract (if there are any).

To request a transaction’s receipt, you can call the getTransactionReceipt() method instead. Just replace your `getTransaction()` call with this snippet:

const tx = await thor.transactions.getTransactionReceipt(
    '0x1228fa0f179d046c0245d2fe9f4cea5f93df0c74c25e7561f69325bc137b642e'
);
console.log(tx);

Example of a Successful Transaction:

{
  type: 81,
  gasUsed: 148354,
  gasPayer: '0x75e11b7e879529005585971bcdec60fc11262dd5',
  paid: '0x14d5f5b24594c430',
  reward: '0x3f5ded2f7f8430',
  reverted: false,
  meta: {
    blockID: '0x0151f1f6378b680cbd87c147aa305fd46778c5fc41258de8bf2632303ae897aa',
    blockNumber: 22147574,
    blockTimestamp: 1752005110,
    txID: '0x1228fa0f179d046c0245d2fe9f4cea5f93df0c74c25e7561f69325bc137b642e',
    txOrigin: '0x75e11b7e879529005585971bcdec60fc11262dd5'
  },
  outputs: [ { contractAddress: null, events: [Array], transfers: [Array] } ]
}