Tools · Bridges & conversion

Loop

Lightning Labs' non-custodial liquidity bridge — Loop Out and Loop In move balance between Lightning and on-chain via submarine swaps.

What it is

Loop is Lightning Labs’ non-custodial liquidity tool for LND nodes. Loop Out moves Lightning balance to on-chain (the canonical way to sweep an operational balance back to L1 cold-storage reserves); Loop In does the reverse. Both use submarine swaps, so they’re atomic and non-custodial. It’s the standard mechanism behind the hot/cold treasury sweep the Stack describes — making it a practical bridge between the payment layer and the settlement layer.

It moves value within the Bitcoin stack — Lightning ↔ L1 — so it’s substrate tooling: the L1↔Lightning phase change, not a crossing to the legacy economy. See The Stack §1 for the reserve-sweep role.

When to use it

• Sweeping an agent’s operational Lightning balance back to on-chain reserves (Loop Out).
• Acquiring inbound Lightning liquidity from on-chain funds (Loop In).
• Treasury liquidity management for an LND-based agent stack.

Dependencies

An LND node — backed by a Bitcoin node (Bitcoin Core, or Neutrino) — with both Lightning and on-chain balance to move between, plus access to Lightning Labs’ Loop server (non-custodial via atomic swaps, but not a permissionless market — you depend on its availability and pricing); on-chain fees apply to each swap.

Quick start

Run Loop against an LND node — repo at github.com/lightninglabs/loop, product page at lightning.engineering/loop/. Recent releases can even open Lightning channels directly from static-address deposits (loop openchannel).

Gotchas

• Still beta software (every release is -beta).
• Swaps execute against Lightning Labs’ Loop server — non-custodial (atomic), but you depend on that server’s availability and pricing; it’s not a permissionless market.
• Primarily targets LND node operators; on-chain fees apply to each swap.