Lightning Loop

Lightning Loop is a non-custodial service offered by Lightning Labs that makes it easy to move bitcoin into and out of the Lightning Network.

Features

• Automated channel balancing
• Privacy-forward non-custodial swaps
• Opportunistic transaction batching to save on fees
• Instant Loop-Outs for faster off-chain to on-chain swaps
• Static, reusable addresses for Loop-Ins
• Progress monitoring of in-flight swaps

Use Cases

• Automate channel balancing with AutoLoop (Learn more)
• Deposit to a Bitcoin address without closing channels with Loop In
• Convert outbound liquidity into inbound liquidity with Loop Out
• Refill depleted Lightning channels with Loop In

Installation

Download the latest binaries from the releases page.

Execution

The Loop client needs its own short-lived daemon to facilitate swaps. To start loopd:

loopd

To use Loop in testnet, simply pass the network flag:

loopd --network=testnet

By default loopd attempts to connect to the lnd instance running on localhost:10009 and reads the macaroon and tls certificate from ~/.lnd. This can be altered using command line flags. See loopd --help.

Usage

AutoLoop

AutoLoop makes it easy to keep your channels balanced. Checkout our autoloop documentation for details.

Loop Out

Use Loop Out to move bitcoins on Lightning into an on-chain Bitcoin address.

To execute a Loop Out:

loop out <amt_in_satoshis>

Other notable options:

• Use the --fast flag to swap immediately (Note: This opts-out of fee savings made possible by transaction batching)
• Use the --channel flag to loop out on specific channels
• Use the --addr flag to specify the address the looped out funds should be sent to (Note: By default funds are sent to the lnd wallet)

Run loop monitor to monitor the status of a swap.

Loop In

Use Loop In to convert on-chain bitcoin into spendable Lightning funds.

To execute a Loop In:

loop in <amt_in_satoshis>

More info

• Loop FAQs
• Loop CLI manual

Development

Regtest

To get started with local development against a stripped down dummy Loop server running in a local regtest Bitcoin network, take a look at the regtest server environment example documentation.

Testnet

To use Loop in testnet, simply pass the network flag:

loopd --network=testnet

Submit feature requests

The GitHub issue tracker can be used to request specific improvements or report bugs. Do not use public issues for security disclosures. Follow the instructions in SECURITY.md.

Join us on Slack

Join us on the LND Slack and join the #loop channel to ask questions and interact with the community.

LND

Note that Loop requires lnd to be built with all of its subservers. Download the latest official release binary or build lnd from source by following the installation instructions. If you choose to build lnd from source, use the following command to enable all the relevant subservers:

make install tags="signrpc walletrpc chainrpc invoicesrpc"

API

The Loop daemon exposes a gRPC API (defaults to port 11010) and a REST API (defaults to port 8081).

The gRPC and REST connections of loopd are encrypted with TLS and secured with macaroon authentication the same way lnd is.

If no custom loop directory is set then the TLS certificate is stored in ~/.loop/<network>/tls.cert and the base macaroon in ~/.loop/<network>/loop.macaroon.

The loop command will pick up these file automatically on mainnet if no custom loop directory is used. For other networks it should be sufficient to add the --network flag to tell the CLI in what sub directory to look for the files.

For more information on macaroons, see the macaroon documentation of lnd.

NOTE: Loop's macaroons are independent from lnd's. The same macaroon cannot be used for both loopd and lnd.

Build from source

If you’d prefer to build from source:

git clone https://github.com/lightninglabs/loop.git
cd loop/cmd
go install ./...

Reproducible builds

If you want to build release files yourself, follow the guide.