Deposit and mint

The main feature of the tBTC bridge is depositing BTC and using it to mint the ERC-20 TBTC token. This guide explains how to perform this process using the SDK.

Initialize the SDK

First, initialize the SDK, as described in the Initialize SDK guide.

Initiate the deposit

Once the SDK is initialized, you can initiate the deposit and get their Bitcoin address in the following way:

import { TBTC } from "@keep-network/tbtc-v2.ts"

// Initialized SDK.
const sdk: TBTC

// Set the P2WPKH/P2PKH Bitcoin recovery address. It can be used to recover
// deposited BTC in case something exceptional happens.
const bitcoinRecoveryAddress: string = "..."

// Initiate the deposit.
const deposit = await sdk.deposits.initiateDeposit(bitcoinRecoveryAddress)

// Take the Bitcoin deposit address. BTC must be sent here.
const bitcoinDepositAddress = await deposit.getBitcoinAddress()

Make the Bitcoin deposit transaction

The next step is doing the actual Bitcoin deposit transaction to the deposit address. There are two possible ways to do so:

• Recommended: Use an external Bitcoin wallet

• Non-recommended: Use the experimental SDK DepositFunding component. This code is used for testing purposes and is not safe for production use!

Initiate minting

Once the Bitcoin deposit transaction is done, minting can be initiated. This can be done using the initiateMinting method exposed by the Deposit class. This method has two modes:

• Automatic: Automatically detect the latest funding UTXO and use it to initiate minting. This mode is the default one that should be used when a single Bitcoin deposit transaction has been made.

• Manual: Take a funding UTXO as a parameter and use it to initiate minting. This mode can be useful when multiple Bitcoin deposit transactions target the same deposit address.

Here is an example of both:

Automatic

// Initiate minting using latest funding UTXO. Returns hash of the
// initiate minting transaction. Can throw an error if there are no
// Bitcoin funding transactions targeting this deposit address. 
// In that case, consider retrying after a delay.
const txHash = await deposit.initiateMinting()

Manual

// Detect funding UTXOs manually. There can be more than one.
await fundingUTXOs = await deposit.detectFunding()

// Initiate minting using one of the funding UTXOs. Returns hash of the
// initiate minting transaction.
const txHash = await deposit.initiateMinting(fundingUTXOs[0])