BDK

A modern, lightweight, descriptor-based wallet library written in Rust!

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About

The bdk library aims to be the core building block for Bitcoin wallets of any kind.

• It uses Miniscript to support descriptors with generalized conditions. This exact same library can be used to build single-sig wallets, multisigs, timelocked contracts and more.
• It supports multiple blockchain backends and databases, allowing developers to choose exactly what's right for their projects.
• It's built to be cross-platform: the core logic works on desktop, mobile, and even WebAssembly.
• It's very easy to extend: developers can implement customized logic for blockchain backends, databases, signers, coin selection, and more, without having to fork and modify this library.

Examples

Sync the balance of a descriptor

use bdk::Wallet;
use bdk::database::MemoryDatabase;
use bdk::blockchain::ElectrumBlockchain;
use bdk::SyncOptions;

use bdk::electrum_client::Client;

fn main() -> Result<(), bdk::Error> {
    let blockchain = ElectrumBlockchain::from(Client::new("ssl://electrum.blockstream.info:60002")?);
    let wallet = Wallet::new(
        "wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/0/*)",
        Some("wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/1/*)"),
        bitcoin::Network::Testnet,
        MemoryDatabase::default(),
    )?;

    wallet.sync(&blockchain, SyncOptions::default())?;

    println!("Descriptor balance: {} SAT", wallet.get_balance()?);

    Ok(())
}

Generate a few addresses

use bdk::{Wallet, database::MemoryDatabase};
use bdk::wallet::AddressIndex::New;

fn main() -> Result<(), bdk::Error> {
    let wallet = Wallet::new(
        "wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/0/*)",
        Some("wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/1/*)"),
        bitcoin::Network::Testnet,
        MemoryDatabase::default(),
    )?;

    println!("Address #0: {}", wallet.get_address(New)?);
    println!("Address #1: {}", wallet.get_address(New)?);
    println!("Address #2: {}", wallet.get_address(New)?);

    Ok(())
}

Create a transaction

use bdk::{FeeRate, Wallet, SyncOptions};
use bdk::database::MemoryDatabase;
use bdk::blockchain::ElectrumBlockchain;

use bdk::electrum_client::Client;
use bdk::wallet::AddressIndex::New;

use bitcoin::consensus::serialize;

fn main() -> Result<(), bdk::Error> {
    let blockchain = ElectrumBlockchain::from(Client::new("ssl://electrum.blockstream.info:60002")?);
    let wallet = Wallet::new(
        "wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/0/*)",
        Some("wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/1/*)"),
        bitcoin::Network::Testnet,
        MemoryDatabase::default(),
    )?;

    wallet.sync(&blockchain, SyncOptions::default())?;

    let send_to = wallet.get_address(New)?;
    let (psbt, details) = {
        let mut builder = wallet.build_tx();
        builder
            .add_recipient(send_to.script_pubkey(), 50_000)
            .enable_rbf()
            .do_not_spend_change()
            .fee_rate(FeeRate::from_sat_per_vb(5.0));
        builder.finish()?
    };

    println!("Transaction details: {:#?}", details);
    println!("Unsigned PSBT: {}", base64::encode(&serialize(&psbt)));

    Ok(())
}

Sign a transaction

use bdk::{Wallet, SignOptions, database::MemoryDatabase};

use bitcoin::consensus::deserialize;

fn main() -> Result<(), bdk::Error> {
    let wallet = Wallet::new(
        "wpkh([c258d2e4/84h/1h/0h]tprv8griRPhA7342zfRyB6CqeKF8CJDXYu5pgnj1cjL1u2ngKcJha5jjTRimG82ABzJQ4MQe71CV54xfn25BbhCNfEGGJZnxvCDQCd6JkbvxW6h/0/*)",
        Some("wpkh([c258d2e4/84h/1h/0h]tprv8griRPhA7342zfRyB6CqeKF8CJDXYu5pgnj1cjL1u2ngKcJha5jjTRimG82ABzJQ4MQe71CV54xfn25BbhCNfEGGJZnxvCDQCd6JkbvxW6h/1/*)"),
        bitcoin::Network::Testnet,
        MemoryDatabase::default(),
    )?;

    let psbt = "...";
    let mut psbt = deserialize(&base64::decode(psbt).unwrap())?;

    let finalized = wallet.sign(&mut psbt, SignOptions::default())?;

    Ok(())
}

Testing

Unit testing

cargo test

Integration testing

Integration testing require testing features, for example:

cargo test --features test-electrum

The other options are test-esplora or test-rpc. Note that electrs and bitcoind binaries are automatically downloaded (on mac and linux), to specify you already have installed binaries you must use --no-default-features and provide BITCOIND_EXE and ELECTRS_EXE as environment variables.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.