Struct CommitmentTxBuilder 

pub struct CommitmentTxBuilder {
    pub fee_rate_sat_per_vb: u64,
    pub protocol_id: [u8; 32],
    pub max_fee_rate_sat_per_vb: u64,
    pub dust_threshold_sat: u64,
}

Configuration for building commitment transactions

Fields

fee_rate_sat_per_vb: u64

Fee rate in sat/vB

protocol_id: [u8; 32]

Protocol ID for this commitment

max_fee_rate_sat_per_vb: u64

Maximum fee rate to prevent overpaying

dust_threshold_sat: u64

Dust threshold (satoshi)

Implementations

impl CommitmentTxBuilder

pub fn new(protocol_id: [u8; 32], fee_rate_sat_per_vb: u64) -> Self

Create a new transaction builder

pub fn with_fee_rate(self, fee_rate: u64) -> Self

Set the fee rate

pub fn with_max_fee_rate(self, max_fee: u64) -> Self

Set maximum fee rate (prevents overpaying during fee spikes)

pub fn estimate_vbytes(input_count: usize, output_count: usize) -> usize

Estimate virtual bytes for a commitment transaction

pub fn calculate_fee(&self, input_count: usize, output_count: usize) -> u64

Calculate required fee

pub fn is_above_dust(&self, value_sat: u64) -> bool

Check if an output amount is above the dust threshold

pub fn build_commitment_tx( &self, wallet: &SealWallet, seal_utxo: &WalletUtxo, commitment_hash: [u8; 32], _change_path: Option<&Bip86Path>, ) -> Result<CommitmentTxResult, TxBuilderError>

Build a complete commitment transaction

This handles two cases:

1. Plain P2TR input (funded externally to a simple P2TR address): The input is spent via key-path using the tweaked keypair. The output uses a Tapret commitment with the same internal key.

2. Tapret input (previously committed): The input is spent via script-path using the tapret leaf.

For freshly funded UTXOs (case 1), this is the standard flow.

pub fn build_commitment_data(&self, commitment: Hash) -> CommitmentData

Build legacy commitment data (for backward compatibility)