OpenClaw · Skill
Hedera Tx Builder
Provides TypeScript patterns for building, signing, and submitting transactions on the Hedera network using the official Hashgraph SDK. Covers HBAR transfers, token association, account creation, and topic messaging.
Install
Start with the primary install command. Alternate entrypoints are included below for ClawHub and OpenClaw CLI users.
Primary command
clawhub install harleyscodes/hedera-tx-builderClawHub installer
npx clawhub@latest install harleyscodes/hedera-tx-builderOpenClaw CLI
openclaw skills install harleyscodes/hedera-tx-builderDirect OpenClaw install
openclaw install harleyscodes/hedera-tx-builderWhat this skill does
Provides TypeScript patterns for building, signing, and submitting transactions on the Hedera network using the official Hashgraph SDK. Covers HBAR transfers, token association, account creation, and topic messaging.
Why it matters
The Hashgraph SDK handles transaction serialization, fee calculation, and network submission so you don't have to construct raw gRPC calls manually.
Typical use cases
- Sending HBAR between accounts programmatically
- Associating a wallet with a new token before receiving it
- Creating new Hedera accounts with an initial balance
- Publishing messages to a Hedera Consensus Service topic
- Calling smart contracts on Hedera mainnet or testnet
Source instructions
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