name: hedera-tx-builder description: Build and sign Hedera transactions. Use for: (1) Creating HBAR transfers, (2) Token operations, (3) Smart contract calls, (4) Submitting to Hedera network.

Hedera Transaction Builder

Setup

npm install @hashgraph/sdk

Client Setup

import { Client, AccountBalanceQuery, Hbar } from '@hashgraph/sdk';

const client = Client.forMainnet();
// Or for testnet:
const client = Client.forTestnet();

Transfer HBAR

import { TransferTransaction, Hbar } from '@hashgraph/sdk';

const tx = new TransferTransaction()
  .addHbarTransfer(fromAccountId, new Hbar(-100)) // send
  .addHbarTransfer(toAccountId, new Hbar(100))    // receive
  .setTransactionMemo("Payment for goods");

// Sign with hashpack or operator
const signTx = await tx.sign(operatorKey);
const result = await signTx.execute(client);

Key Transaction Types

AccountCreate

new AccountCreateTransaction()
  .setKey(publicKey)
  .setInitialBalance(new Hbar(10))
  .setAccountMemo("My account");

TokenAssociate

new TokenAssociateTransaction()
  .setAccountId(accountId)
  .setTokenIds([tokenId1, tokenId2]);

TopicMessage

new TopicMessageTransaction()
  .setTopicId(topicId)
  .setMessage("Hello Hedera!");

Network Endpoints

• Mainnet: https://mainnet.hashio.io/api
• Testnet: https://testnet.hashio.io/api

Important Concepts

• Hbar: 1 HBAR = 100,000,000 tinybars
• Account ID: Format shard.realm.num (e.g., 0.0.12345)
• Transaction Fee: Small HBAR fee for each transaction
• Transaction Valid Duration: 180 seconds by default