Ramps: Boarding and Exiting

Ramps are the mechanisms that allow users with Bitcoin to onboard and exit from Arkade with its own built-in mechanisms. They are designed to provide a seamless experience for users, allowing them to move funds in and out of Arkade. There are two types of ramps: Boarding (onboarding) and Exiting (offboarding).

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Boarding

Boarding is the process of swapping an on-chain UTXO for an off-chain VTXO. The preferred method for onboarding funds into Arkade is by sending Bitcoin to a boarding address.

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1. Generate a boarding address

First, get a boarding address from your wallet. This is a specialized 2-of-2 multisig Taproot address.

// Get a boarding address
const addresses = await wallet.getAddress()
console.log('Boarding Address:', addresses.boarding)

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2. Send Bitcoin to the boarding address

Send Bitcoin to this address using any standard Bitcoin wallet. This creates an on-chain UTXO that will be used for boarding.

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3. Check for boarding UTXOs and settle them to your wallet

Once the transaction is confirmed, check for available boarding UTXOs and settle them to your Arkade wallet.

// Settle all VTXOs and boarding UTXOs to your own address
const settleTxid = await wallet.settle()

console.log('Settlement transaction ID:', settleTxid)

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4. Operator includes the UTXO in a Commitment Transaction

The Arkade Operator processes the registration and includes the UTXO in a Commitment Transaction.

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5. Receive a VTXO

Once the Commitment Transaction is confirmed, you now have a VTXO (Virtual UTXO) within a Batch Output that you can spend off-chain.

While any UTXO can be used as an input, a boarding address is the preferred way as it removes the risk of a malicious user double-spending the UTXO and replacing or failing the commitment transaction.

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Exiting

Exiting is the process of swapping a VTXO (off-chain) for a UTXO (on-chain). The collaborative exit process is the most efficient way to exit Arkade when the Operator is available.

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1. Gather available inputs

First, collect all available inputs, including both VTXOs and boarding UTXOs.

// Get all available inputs (both VTXOs and boarding UTXOs)
const inputs = (await Promise.all([
  wallet.getVtxos(),
  wallet.getBoardingUtxos()
])).flat()

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2. Specify destination and amount

Specify the destination address and amount for the on-chain UTXO.

// Specify destination address and amount
const destinationAddress = "bc1q..." // Your on-chain Bitcoin address
const amount = 50000 // Amount in sats

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3. Request settlement

Request the Arkade Operator to settle your VTXO to an on-chain UTXO.

// Settle to an on-chain address
const settleTxid = await wallet.settle({
  inputs,
  outputs: [{
    address: destinationAddress,
    amount: BigInt(amount)
  }]
})

console.log('Settlement transaction ID:', settleTxid)

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4. Operator processes and broadcasts

The Operator includes this request in a new Commitment Transaction and broadcasts it to the Bitcoin network.

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5. Receive on-chain funds

Once confirmed, your funds are available as a standard on-chain Bitcoin UTXO.

This method offers immediate withdrawal with lower delay and is operationally simpler than unilateral exits.

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Unilateral Exit

Unilateral exit is the process of exiting a VTXO to an on-chain address without the Operator’s involvement. This is a more complex and expensivie process and should only be done if the Operator is not available.

// Unilateral exit all vtxos
await wallet.exit();

// Unilateral exit a specific vtxo
await wallet.exit([{ txid: vtxo.txid, vout: vtxo.vout }]);