NotATether: Create Splicing stub (option_splice / interactive construction)

2026-09-12T03:10:19Z

Create Splicing stub (option_splice / interactive construction)

New page

'''Splicing''' is a [[Lightning Network]] protocol that spends a channel's current funding output into a new funding output with a different amount, so peers can add or remove on-chain funds without closing the channel. Feature bits 62/63 advertise <code>option_splice</code>. The construction reuses interactive transaction building from [[Dual funding]].

Without splicing, changing capacity usually means a close and a new open, which is slower, costs more on-chain fees, and drops the channel from the public graph while it is down. A splice-in adds funds. A splice-out withdraws to an on-chain address. Moving value into another of the same node's channels is sometimes called a cross-splice.

Peers first quiesce the channel (BOLT 2 <code>option_quiesce</code> / <code>stfu</code>) so both sides share the same committed state with no in-flight updates. They then negotiate amounts and feerate, build a transaction that spends the current funding output (plus any extra inputs) into a new funding output and optional splice-out outputs, and exchange signatures for that splice and for commitments that spend the new outpoint. Commitments that still spend the old outpoint are kept until the splice confirms. After un-quiescing, new HTLCs must remain valid against every pending funding outpoint so a late confirmation cannot strand a payment. The splice may be fee-bumped with [[Replace by fee]] by repeating construction. When a splice reaches the required depth, peers exchange <code>splice_locked</code>, drop competing pending splices and the old funding outpoint, and advertise the new short channel id.

Splicing needs no consensus change. Taproot channels splice into a new P2TR funding output. Legacy channels splice into a new P2WSH 2-of-2. Until <code>splice_locked</code>, watchers must track every pending funding outpoint.

== See also ==
* [[Dual funding]]
* [[Lightning Network]]
* [[Replace by fee]]

== External links ==
* [https://bitcoinops.org/en/topics/splicing/ Bitcoin Optech: Splicing]
* [https://github.com/lightning/bolts/blob/master/02-peer-protocol.md BOLT 2: Peer Protocol for Channel Management]
* [https://github.com/lightning/bolts/pull/1160 BOLTs PR 1160: Channel Splicing]

[[Category:Technical]]

Splicing - Revision history

NotATether: Create Splicing stub (option_splice / interactive construction)