Splicing (Bitcoin Optech Topics)

This Bitcoin Optech topic page is a neutral technical explainer of splicing, a Lightning feature that lets users add funds to (splice-in) or remove funds from (splice-out) an existing payment channel without closing it and opening a new one.

It distinguishes splicing from related techniques such as submarine swaps, noting that in a submarine swap the channel's overall balance stays the same, whereas splicing actually changes it. That difference is why splicing matters for liquidity management: it lets a channel grow or shrink in place.

Usefully, the page tracks implementation progress across multiple Lightning projects, including Core Lightning, Eclair, LDK, LND, and Phoenix, and links the newsletter coverage that documents how the feature has matured over time.

It is a good example of an active engineering frontier moving from proposal to uneven, real-world deployment.