What's inside?

This package allows to easily implement sBTC deposits and withdrawals into Node.js apps and services. The provided functions and helpers provide an interface to the on-chain contracts deployed on mainnet, testnet, and devnet.

Installation

npm i @double-spent/sbtc-core

Usage

Deposit BTC for sBTC

Depositing sBTC involves sending BTC over the Bitcoin network to the sBTC bridge and receive sBTC on the Stacks network. This can be achieved with the submitSbtcDeposit function, which creates a Bitcoin PSBT (partially-signed Bitcoin transaction) to send the specified amount and broadcasts it to the network.

submitSbtcDeposit is not tied to a particular wallet, so it requires the callback used to sign the PSBT to be passed in the arguments. The example below uses the Leather Wallet.

import { submitSbtcDeposit, SbtcNetwork } from '@double-spent/sbtc-core';

// Load user data from a connected wallet

const user = userSession.loadUserData();

const stacksAddress = user.profile.stxAddress.testnet;
const bitcoinAddress = user.profile.btcAddress.p2wpkh.testnet;
const bitcoinPublicKey = user.profile.btcPublicKey.p2wpkh;

// Define a callback to sign PSBTs with Leather

const signPsbt = async (request) => {
  return await (window as any).btc.request('signPsbt', request).result.hex;
};

const satsAmount = 5_000;
const network = SbtcNetwork.TESTNET;

// Submit the sBTC deposit

const btcTransactionHash = await submitSbtcDeposit({
  network,
  stacksAddress,
  bitcoinAddress,
  bitcoinPublicKey,
  satsAmount,
  signPsbt,
});

// Print the transaction hash

console.log({ btcTransactionHash });

The submitSbtcDeposit function takes the following arguments:

| Argument | Type | Description | | ------------------ | --------------------------------------------- | ---------------------------------------------------------------- | | satsAmount | number | The amount in satoshis to deposit. | | stacksAddress | string | The sender's Stacks address where the sBTC will be sent. | | bitcoinAddress | string | The sender's Bitcoin address where the BTC is deposited from. | | bitcoinPublicKey | string | The sender's Bitcoin public key used to sign the deposit PSBT. | | network | SbtcNetwork | The network to use. | | feeRateTarget | SbtcDepositFeeRate | The target fee rate to use (low, medium, high). | | signPsbt | SbtcSignPsbtCallback | The callback used to sign PSBTs before broadcasting the deposit. |

Withdraw sBTC for BTC

Withdrawing BTC for sBTC involves sending sBTC over the Stacks network to the bridge and receiving BTC on the Bitcoin network. This requires two steps: to sign the withdrawal with a Stacks wallet and submit the withdrawal via a PSBT. The signSbtcWithdrawal and submitSbtcWithdrawal function are used to achieve both steps. submitSbtcWithdrawal works similar to submitSbtcDeposit but it takes the signature resulting from calling signSbtcWithdrawal.

signSbtcWithdrawal and submitSbtcWithdrawal are not tied to a particular wallet, so they require callbacks used to sign messages and sign the PSBT to be passed in the arguments. The example below uses the Leather Wallet.

Sign the withdrawal

import { openSignatureRequestPopup } from '@stacks/connect';
import { signSbtcWithdrawal, SbtcNetwork } from '@double-spent/sbtc-core';

// Load user data from a connected wallet

const user = userSession.loadUserData();
const bitcoinAddress = user.profile.btcAddress.p2wpkh.testnet;

// Define a callback to sign messages using Leather

const signMessage = async ({ message, stacksNetwork }) => {
  return await new Promise((resolve) => {
    openSignatureRequestPopup({
      message,
      userSession,
      network: stacksNetwork,
      onFinish: (data) => {
        resolve(data.signature);
      },
    });
  });
};

const satsAmount = 5_000;
const network = SbtcNetwork.TESTNET;

// Sign the sBTC withdrawal

const signature = await signSbtcWithdrawal({
  bitcoinAddress,
  satsAmount,
  network,
  signMessage,
});

// Print the transaction hash

console.log({ signature });

The signSbtcWithdrawal function takes the following arguments:

| Argument | Type | Description | | ---------------- | --------------------------------------------------- | ------------------------------------------------------------- | | satsAmount | number | The amount in satoshis to withdraw. | | bitcoinAddress | string | The sender's Bitcoin address where the BTC will be withdrawn. | | signature | string | The signature authorizing the withdrawal. | | network | SbtcNetwork | The network to use. | | feeRateTarget | SbtcDepositFeeRate | The target fee rate to use (low, medium, high). | | signMessage | SbtcSignMessageCallback | The callback used to sign the message. |

Submit the withdrawal

import { submitSbtcWithdrawal, SbtcNetwork } from '@double-spent/sbtc-core';

// Load user data from a connected wallet

const user = userSession.loadUserData();

const bitcoinAddress = user.profile.btcAddress.p2wpkh.testnet;
const bitcoinPublicKey = user.profile.btcPublicKey.p2wpkh;

// Define a callback to sign PSBTs using Leather

const signPsbt = async (request) => {
  return await (window as any).btc.request('signPsbt', request).result.hex;
};

const satsAmount = 5_000;
const network = SbtcNetwork.TESTNET;

const signature = await signSbtcWithdrawal({
  // .. sign withdrawal args
});

// Submit the sBTC deposit

const btcTransactionHash = await submitSbtcWithdrawal({
  network,
  bitcoinAddress,
  bitcoinPublicKey,
  satsAmount,
  signature,
  signPsbt,
});

// Print the transaction hash

console.log({ btcTransactionHash });

The submitSbtcWithdrawal function takes the following arguments:

| Argument | Type | Description | | ------------------ | --------------------------------------------- | ------------------------------------------------------------------- | | satsAmount | number | The amount in satoshis to withdraw. | | bitcoinAddress | string | The sender's Bitcoin address where the BTC will be withdrawn to. | | bitcoinPublicKey | string | The sender's Bitcoin public key used to sign the withdrawal PSBT. | | network | SbtcNetwork | The network to use. | | signPsbt | SbtcSignPsbtCallback | The callback used to sign PSBTs before broadcasting the withdrawal. |

Supported features

| Feature | Mode | Status | | ------------- | ----------- | ------------ | | sBTC Devnet | | ✅ Supported | | sBTC Testnet | | ✅ Supported | | sBTC Mainnet | | 🟡 Pending | | Deposit sBTC | OP_RETURN | ✅ Supported | | Withdraw sBTC | OP_RETURN | ✅ Supported | | Deposit sBTC | OP_DROP | 🟡 Pending | | Withdraw sBTC | OP_DROP | 🟡 Pending |

References

• sBTC Bridge
• sBTC Official Documentation
• sbtc NPM Package