Rust-Lightning is a Bitcoin Lightning library written in Rust. The main crate, lightning, does not handle networking, persistence, or any other I/O. Thus, it is runtime-agnostic, but users must implement basic networking logic, chain interactions, and disk storage. The project implements all of the BOLT specifications in the 1.0 spec. The implementation has pretty good test coverage that is expected to continue to improve. It is also anticipated that as developers begin using the API, the lessons from that will result in changes to the API, so any developer using this API at this stage should be prepared to embrace that. LDK/Rust-Lightning is a generic library which allows you to build a lightning node without needing to worry about getting all of the lightning state machine, routing, and on-chain punishment code (and other chain interactions) exactly correct. Note that Rust-Lightning isn't, in itself, a node.