Build an unsigned transaction

import { getPublicKeyFromPrivate } from "@stacks/encryption";
import { 
  makeUnsignedSTXTokenTransfer,
  makeUnsignedContractCall,
  Cl,
  AnchorMode,
  PostConditionMode
} from "@stacks/transactions";
import { STACKS_TESTNET } from "@stacks/network";

// Get public key from private key
const privateKey = "753b7cc01a1a2e86221266a154af739463fce51219d97e4f856cd7200c3bd2a601";
const publicKey = getPublicKeyFromPrivate(privateKey);

// Build unsigned STX transfer
const unsignedTx = await makeUnsignedSTXTokenTransfer({
  recipient: "ST1SJ3DTE5DN7X54YDH5D64R3BCB6A2AG2ZQ8YPD5",
  amount: 1000000n, // 1 STX in micro-STX
  fee: 200n,
  nonce: 0n,
  network: STACKS_TESTNET,
  memo: "Test transfer",
  publicKey,
  anchorMode: AnchorMode.Any,
  postConditionMode: PostConditionMode.Deny,
});

// Transaction is ready for external signing
console.log("Unsigned transaction created:", unsignedTx.txid());

import { makeUnsignedContractCall } from "@stacks/transactions";

const unsignedContractCall = await makeUnsignedContractCall({
  contractAddress: "ST1PQHQKV0RJXZFY1DGX8MNSNYVE3VGZJSRTPGZGM",
  contractName: "my-contract",
  functionName: "transfer",
  functionArgs: [
    Cl.uint(100),
    Cl.principal("ST1SJ3DTE5DN7X54YDH5D64R3BCB6A2AG2ZQ8YPD5")
  ],
  fee: 1000n,
  nonce: 1n,
  network: STACKS_TESTNET,
  publicKey,
  anchorMode: AnchorMode.Any,
});

import { TransactionSigner, deserializeTransaction } from "@stacks/transactions";

// Later, sign the transaction
const serializedTx = unsignedTx.serialize();

// Deserialize and sign
const txToSign = deserializeTransaction(serializedTx);
const signer = new TransactionSigner(txToSign);

// Sign with private key (in practice, this would be done by hardware wallet)
signer.signOrigin(privateKey);

// Get the signed transaction
const signedTx = signer.transaction;

// Broadcast the signed transaction
const broadcastResponse = await broadcastTransaction({
  transaction: signedTx,
  network: STACKS_TESTNET,
});

// 1. Create unsigned transaction
const unsignedTx = await makeUnsignedSTXTokenTransfer({
  recipient: recipientAddress,
  amount: amount,
  fee: fee,
  network: STACKS_TESTNET,
  publicKey: hardwareWalletPublicKey,
});

// 2. Serialize for transport
const serialized = unsignedTx.serialize().toString('hex');

// 3. Send to hardware wallet for signing
// (Implementation depends on wallet SDK)

// 4. Receive signed transaction back
const signedTxHex = await hardwareWallet.signTransaction(serialized);

// 5. Deserialize and broadcast
const signedTx = deserializeTransaction(Buffer.from(signedTxHex, 'hex'));
const result = await broadcastTransaction({ 
  transaction: signedTx,
  network: STACKS_TESTNET,
});