Creating meaningful unit tests can be difficult – even more when the system under test is a transport layer protocol like the Bitcoin wire protocol.

Happy 2025 to all Swift and Bitcoin devs! And Happy 16th Birthday to the Bitcoin network! I wanted to use the occasion for posting an update of where the project stands today and where it could go from here.

So far this year the focus has shifted a bit from getting the client fluent in the peer-to-peer language protocol to making important refinements to many of the public APIs offered by the package.

Last year the development of Swift Bitcoin really kicked off. All research work done on the swift-bitcoin-poc repo was carefully moved over and improved. This includes the transaction model and script engine with full segwit and taproot support.

The ultimate goal for Swift Bitcoin is to become the most comprehensive SDK for bitcoin in Swift with features like mempool management, block mining and connectivity via the bitcoin protocol.

Swift Bitcoin aka The Swift Bitcoin Library is a new project intended for Swift developers who want to build a bitcoin product.