A blockchain-agnostic coin selection library built in Rust.
The library will perform coin selection via various algorithms through a well-documented API. The API will be generic in nature and will not assume any Bitcoin structure or methods. It can be used for any UTXO-based blockchain.
The following algorithms are implemented from scratch in Rust:
- Knapsack
- Branch and Bound
- Lowest Larger
- First-In-First-Out
- Single-Random-Draw
The library will have individual APIs for each algorithm and provide a wrapper API select_coin() which will perform selection via each algorithm and return the result with the least waste metric.
Bitcoin specific example is given here.
In general the example usage is given below,
let utxos: Vec<UTXO> = vec![<utxo1>, <utxo2>, ..., <utxon>]; // List of the available UTXOs
let output_groups: Vec<OutputGroup> = utxos.iter().map(|utxo| convert_utxo_to_output(utxo)).collect();
let options = CoinSelectionOpt {
target_value: 4_000_000u64,
target_fee_rate: 0.5f32,
long_term_feerate: Some(0.3f32),
min_absolute_fee: 1000u64,
base_weight: 72u32,
change_weight: 18u32,
change_cost: 250u64,
cost_per_input: 300u64,
cost_per_output: 250u64,
min_change_value: 1_000u64,
excess_strategy: ExcessStrategy::ToChange,
};
let selection_output = select_coin(&output_groups, options);
println!("Estimated waste = {}", selection_output.waste);
println!("Indexes of the selected utxos = {}", selection_output.selected_inputs);
let selected_utxos: Vec<UTXO> = selection_output.iter().map(|index| utxos[index]).collect();The convert_utxo_to_output logic should be implemented by yourself for the respective blockchain protocol.
Note that we can group multiple utxos into a single [OutputGroup].
Other characteristics of the library:
- Well-documented code, helpful in understanding coin selection theory.
- Minimal possible dependency footprint.
- Minimum possible MSRV (Minimum Supported Rust Version).
The dev community gathers in a small corner of Discord here (say hello if you drop there from this readme).
Dev discussions predominantly happen via FOSS (Free and Open-Source Software) best practices, and by using GitHub as the Community Forum.
The Issues, PRs, and Discussions are where all the heavy lifting happens.