BDK Roadmap Planning

[notmandatory]

Post high level improvements (fixes, features, refactoring) you'd like to see in a future bdk_wallet or bdk_chain repo release. If you also have a milestone in mind add that (ie. 2.0, 3.0, ...) or a year (2025, 2026, ...). Also add links to any supporting open issues or PRs. Make one post per feature with high level summary, comments go in below reply thread.

[notmandatory]

bdk_wallet: Multi-descriptor Wallets

Currently BDK wallets only support two descriptors, external and optional internal. Supporting multiple descriptors would make it possible to monitor and spend from descriptors with different script types for the same key which the bitcoind wallet does to improve privacy. It would also make it easier to safely roll over from one script type to a new one by changing which descriptors are used for change and new receive addresses, while still monitoring old descriptors for new UTXOs.

This is a large-ish new feature, so I propose we do it for a 4.0 or some time in 2026.

See:
bitcoindevkit/bdk_wallet#28
bitcoindevkit/bdk_wallet#189
bitcoindevkit/bdk_wallet#188

[notmandatory]

This could be done sooner as a non-breaking change if we don't try to change the existing Wallet type and start by creating an "experimental" MultiWallet type instead.

[notmandatory]

bdk_wallet: Replace TxBuilder with bdk-tx crate

The bdk-tx crate is a transaction building library based on rust-miniscript that lets you build, update, and finalize PSBTs. The bdk-tx crate uses the rust-miniscript planning module instead of the bdk_wallet policy module and makes it easier to construct a tx when multiple spending paths are possible. Extracting transaction creation to it's own project will also allow other projects that don't need the full bdk_wallet functionality to use it.

I suggest we focus on only extracting the existing TxBuilder functionality and fixing any bugs we can. New builder features should be added in later releases.

This is a large new feature, but work has already begun on bdk-tx so I propose we target the 3.0 milestone for this feature.

See:
https://github.com/bitcoindevkit/bdk-tx
bitcoindevkit/bdk_wallet#151
bitcoindevkit/bdk_wallet#164
bitcoindevkit/bdk_wallet#15

[notmandatory]

bdk_wallet: Support Multipath Descriptors

This is a frequently requested feature that shouldn't require any big changes to the Wallet constructing functions. The main blocker is deciding what API would make the most sense.

This is a small feature that would great to see in a 2.0, 3.0 or 3.1 milestone.

See:
bitcoindevkit/bdk_wallet#11