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;
use bdk::bitcoin::Network;

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/*)"),
        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;
use bdk::bitcoin::Network;

fn main() -> Result<(), bdk::Error> {
    let wallet = Wallet::new(
        "wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/0/*)",
        Some("wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/1/*)"),
        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 base64;
use bdk::bitcoin::consensus::serialize;
use bdk::bitcoin::Network;

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/*)"),
        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 base64;
use bdk::bitcoin::consensus::deserialize;
use bdk::bitcoin::Network;

fn main() -> Result<(), bdk::Error> {
    let wallet = Wallet::new(
        "wpkh([c258d2e4/84h/1h/0h]tprv8griRPhA7342zfRyB6CqeKF8CJDXYu5pgnj1cjL1u2ngKcJha5jjTRimG82ABzJQ4MQe71CV54xfn25BbhCNfEGGJZnxvCDQCd6JkbvxW6h/0/*)",
        Some("wpkh([c258d2e4/84h/1h/0h]tprv8griRPhA7342zfRyB6CqeKF8CJDXYu5pgnj1cjL1u2ngKcJha5jjTRimG82ABzJQ4MQe71CV54xfn25BbhCNfEGGJZnxvCDQCd6JkbvxW6h/1/*)"),
        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, test-rpc or test-rpc-legacy which runs against an older version of Bitcoin Core. 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.

Running under WASM

If you want to run this library under WASM you will probably have to add the following lines to you Cargo.toml:

[dependencies]
getrandom = { version = "0.2", features = ["js"] }

This enables the rand crate to work in environments where JavaScript is available. See this link to learn more.

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.