Splicing

Splicing is a Lightning protocol improvement that lets users resize channels without closing them and opening new ones. Instead of tearing down an existing channel to add or remove liquidity, a splice updates the channel's funding transaction in place.

The increased liquidity flows improve all aspects of Lightning including payment speed, payment fees, and payment reliability.

— Dusty Daemon

Splicing gives users a cleaner way to add or remove liquidity, helping node operators manage capital more efficiently.

Why fund it?

Splicing has been discussed for years, but turning a specification into production-ready code takes focused engineering. It touches protocol design, transaction construction, edge-case handling, interoperability, and developer education across multiple Lightning implementations.

OpenSats began supporting Splicing in July 2023 through a Bitcoin grant to Dusty Daemon, who has been driving both the specification and the first implementation work. That support later expanded into long-term support as the project matured.

What's next?

The official merging of the splicing specifications in the BOLTs repository has moved this work closer to broader deployment. In the lightning infrastructure impact report, Dusty describes progress on a full implementation in Core Lightning, work on Splice Script for more expressive transaction flows, and parallel efforts to bring Splicing into LDK.

Dusty's latest reports show that the work has shifted from ratifying the spec to shipping usable tools. The splicing spec is now ratified, Core Lightning and Eclair have gone through final interoperability work, and Splice Script now supports multi-channel splices plus simpler splicein and spliceout flows.

The next step is wider interoperability and production adoption. Once multiple Lightning stacks can rely on the same underlying behavior, Splicing can become a standard liquidity tool instead of a niche feature.