Module onchain

Onchain wallet integration interfaces.

This module defines the traits and types that an external onchain wallet must implement to be used by the library. The goal is to let integrators plug in their own wallet implementation, so features like boarding (moving onchain funds into Ark) and unilateral exit (claiming VTXOs onchain without server cooperation) are supported.

Key concepts exposed here:

• Utxo, LocalUtxo & SpendableExit: lightweight types representing wallet UTXOs and spendable exit outputs.
• PreparePsbt & SignPsbt: funding and signing interfaces for building transactions.
• GetBalance, GetWalletTx, GetSpendingTx: read-access to wallet state for balance and Transaction lookups required by various parts of the library.
• MakeCpfp: CPFP construction interfaces used for create child transactions.
• ExitUnilaterally: a convenience trait that aggregates the required capabilities a wallet must provide to support unilateral exits.

A reference implementation based on BDK is available behind the onchain_bdk cargo feature. Enable it to use the provided OnchainWallet implementation. You can use all features from BDK because bdk_wallet is re-exported.

Re-exports

pub use bdk_wallet;

Structs

ChainSource

Client for interacting with the configured on-chain backend.

FeeRates

The FeeRates struct represents the fee rates for transactions categorized by speed or urgency.

LocalUtxo

A standard wallet Utxo owned by the local wallet implementation.

OnchainWallet

BDK-backed onchain wallet implementation.

SpendableExit

A spendable unilateral exit of a Vtxo which can be claimed onchain.

Enums

ChainSourceClient

ChainSourceSpec

Configuration for the onchain data source.

CpfpError

Returned by the bark API when creating a P2A CPFP transaction fails.

MakeCpfpFees

Indicates how fees should be handled by when creating a CPFP bitcoin::Transaction.

Utxo

Represents an onchain UTXO known to the wallet.

Traits

Board

Trait alias for wallets that support boarding.

ExitUnilaterally

Trait alias for wallets that support unilateral exit end-to-end.

GetBalance

Ability to query the wallets’ total balance.

GetSpendingTx

Ability to find wallet-local spends of a specific OutPoint.

GetWalletTx

Ability to look up transactions known to the wallet.

MakeCpfp

Ability to create and persist CPFP transactions for spending P2A outputs.

PreparePsbt

Ability to construct funded PSBTs for specific destinations or to drain the wallet.

SignPsbt

Ability to finalize a Psbt into a fully signed Transaction.

TxBuilderExt

BDK-backed onchain wallet implementation.