LND Lightning Network Skill

LND (Lightning Network Daemon) is a complete implementation of a Lightning Network node. This skill helps you run lnd in Docker for development and testing, with support for multiple backends.

Prerequisites

• Docker and Docker Compose installed
• (Optional) gh CLI for building from GitHub PRs

Quick Start

Start the full regtest stack (Bitcoin Core + LND):

cd ~/.claude/skills/lnd/templates
docker-compose up -d --build   # First time: builds lnd from source (~3-5 min)
docker-compose up -d           # Subsequent runs: uses cached image

This starts:

• lnd-bitcoind: Bitcoin Core 30 in regtest mode with ZMQ
• lnd: LND built from local source

Notes:

• LND is built from source at /users/roasbeef/gocode/src/github.com/lightningnetwork/lnd
• First build takes ~3-5 minutes to compile Go code
• Uses --noseedbackup for testing (no wallet seed required)

Check status:

~/.claude/skills/lnd/scripts/lncli.sh getinfo

Backend Options

LND supports three backend options:

Backend	Description	Best For
bitcoind	Bitcoin Core	Production, regtest development, interop testing
btcd	btcd (Go implementation)	Simnet testing, fast iteration
neutrino	Light client (BIP 157/158)	Testnet, mobile simulation

Standalone Mode (bitcoind backend - default)

cd ~/.claude/skills/lnd/templates
docker-compose up -d

Shared Mode (interop with eclair)

# First start eclair's stack
cd ~/.claude/skills/eclair/templates
docker-compose up -d

# Then start lnd using eclair's bitcoind
cd ~/.claude/skills/lnd/templates
docker-compose -f docker-compose-shared.yml up -d

btcd Mode (simnet)

cd ~/.claude/skills/lnd/templates
docker-compose -f docker-compose-btcd.yml up -d

Neutrino Mode (light client)

cd ~/.claude/skills/lnd/templates
docker-compose -f docker-compose-neutrino.yml up -d

# Or with signet
NETWORK=signet docker-compose -f docker-compose-neutrino.yml up -d

Docker Management

Build Image (from lnd source)

# Build from current source
~/.claude/skills/lnd/scripts/docker-build.sh

# Build from a specific branch
~/.claude/skills/lnd/scripts/docker-build.sh --branch simple-taproot-chans

# Build from a GitHub PR
~/.claude/skills/lnd/scripts/docker-build.sh --pr 1234

# Build from a specific commit
~/.claude/skills/lnd/scripts/docker-build.sh --commit abc123

# Quick PR build (convenience wrapper)
~/.claude/skills/lnd/scripts/build-pr.sh 1234

Start Containers

# Start standalone stack (bitcoind + lnd)
~/.claude/skills/lnd/scripts/docker-start.sh

# Start in shared mode (uses external bitcoind)
~/.claude/skills/lnd/scripts/docker-start.sh --shared

# Start with btcd backend
~/.claude/skills/lnd/scripts/docker-start.sh --btcd

# Start in neutrino mode
~/.claude/skills/lnd/scripts/docker-start.sh --neutrino

# Rebuild before starting
~/.claude/skills/lnd/scripts/docker-start.sh --build

Stop Containers

# Stop containers (preserve data)
~/.claude/skills/lnd/scripts/docker-stop.sh

# Stop and remove volumes (clean state)
~/.claude/skills/lnd/scripts/docker-stop.sh --clean

View Logs

docker logs -f lnd
docker logs -f lnd-bitcoind

Essential lncli Operations

All commands use lncli.sh wrapper which auto-detects the lnd container.

Node Information

# Get node info
~/.claude/skills/lnd/scripts/lncli.sh getinfo

# Get wallet balance (on-chain)
~/.claude/skills/lnd/scripts/lncli.sh walletbalance

# Get channel balance (Lightning)
~/.claude/skills/lnd/scripts/lncli.sh channelbalance

Wallet & Addresses

# Get new address (native SegWit)
~/.claude/skills/lnd/scripts/lncli.sh newaddress p2wkh

# Get new address (nested SegWit)
~/.claude/skills/lnd/scripts/lncli.sh newaddress np2wkh

# Get new Taproot address
~/.claude/skills/lnd/scripts/lncli.sh newaddress p2tr

# Send on-chain
~/.claude/skills/lnd/scripts/lncli.sh sendcoins --addr=<address> --amt=<satoshis>

Connect to Peers

# Connect by URI
~/.claude/skills/lnd/scripts/lncli.sh connect <pubkey>@<host>:9735

# List connected peers
~/.claude/skills/lnd/scripts/lncli.sh listpeers

# Disconnect
~/.claude/skills/lnd/scripts/lncli.sh disconnect <pubkey>

Channel Management

# Open channel
~/.claude/skills/lnd/scripts/lncli.sh openchannel --node_key=<pubkey> --local_amt=1000000

# List channels
~/.claude/skills/lnd/scripts/lncli.sh listchannels

# Get channel balance
~/.claude/skills/lnd/scripts/lncli.sh channelbalance

# Close channel cooperatively
~/.claude/skills/lnd/scripts/lncli.sh closechannel --funding_txid=<txid> --output_index=<n>

# Force close channel
~/.claude/skills/lnd/scripts/lncli.sh closechannel --funding_txid=<txid> --output_index=<n> --force

Payments

# Create invoice
~/.claude/skills/lnd/scripts/lncli.sh addinvoice --amt=<satoshis> --memo="test payment"

# Decode invoice
~/.claude/skills/lnd/scripts/lncli.sh decodepayreq <bolt11_invoice>

# Pay invoice
~/.claude/skills/lnd/scripts/lncli.sh sendpayment --pay_req=<bolt11_invoice>

# List payments
~/.claude/skills/lnd/scripts/lncli.sh listpayments

# List invoices
~/.claude/skills/lnd/scripts/lncli.sh listinvoices

Regtest Development Workflow

1. Start the Stack

cd ~/.claude/skills/lnd/templates
docker-compose up -d

2. Initialize Regtest Environment

# Automated setup: mines blocks, funds lnd wallet
~/.claude/skills/lnd/scripts/regtest-setup.sh

Or manually:

# Mine blocks for coinbase maturity
~/.claude/skills/lnd/scripts/mine.sh 101

# Get lnd address
LND_ADDR=$(~/.claude/skills/lnd/scripts/lncli.sh newaddress p2wkh | jq -r '.address')

# Send funds to lnd
~/.claude/skills/lnd/scripts/bitcoin-cli.sh sendtoaddress $LND_ADDR 10

# Confirm transaction
~/.claude/skills/lnd/scripts/mine.sh 1

# Check balance
~/.claude/skills/lnd/scripts/lncli.sh walletbalance

3. Open a Channel (with second node)

# Connect to peer
~/.claude/skills/lnd/scripts/lncli.sh connect <nodeId>@<host>:9735

# Open 1M sat channel
~/.claude/skills/lnd/scripts/lncli.sh openchannel --node_key=<nodeId> --local_amt=1000000

# Mine blocks to confirm channel
~/.claude/skills/lnd/scripts/mine.sh 6

# Check channel status
~/.claude/skills/lnd/scripts/lncli.sh listchannels

4. Send a Payment

# On receiving node: create invoice
INVOICE=$( lncli addinvoice --amt=50000 --memo="test" | jq -r '.payment_request')

# On sending node: pay invoice
~/.claude/skills/lnd/scripts/lncli.sh sendpayment --pay_req=$INVOICE

Multi-Node Testing

Run multiple lnd nodes for peer-to-peer testing:

Start Multi-Node Stack

# Start alice and bob nodes
~/.claude/skills/lnd/scripts/docker-start.sh --multi --build

# Or with docker-compose directly
cd ~/.claude/skills/lnd/templates
docker-compose -f docker-compose-multi.yml up -d --build

Initialize Multi-Node Environment

# Full setup: fund wallets and open channel between alice and bob
~/.claude/skills/lnd/scripts/multi-node-setup.sh

# Or without channel
~/.claude/skills/lnd/scripts/multi-node-setup.sh --no-channel

Multi-Node Commands

# Use --node flag to specify which node
~/.claude/skills/lnd/scripts/lncli.sh --node alice getinfo
~/.claude/skills/lnd/scripts/lncli.sh --node bob getinfo

# Get pubkeys
ALICE_PUBKEY=$(~/.claude/skills/lnd/scripts/lncli.sh --node alice getinfo | jq -r '.identity_pubkey')
BOB_PUBKEY=$(~/.claude/skills/lnd/scripts/lncli.sh --node bob getinfo | jq -r '.identity_pubkey')

# Connect nodes
~/.claude/skills/lnd/scripts/lncli.sh --node alice connect ${BOB_PUBKEY}@lnd-bob:9735

# Open channel
~/.claude/skills/lnd/scripts/lncli.sh --node alice openchannel --node_key=$BOB_PUBKEY --local_amt=1000000

# Send payment from alice to bob
INVOICE=$(~/.claude/skills/lnd/scripts/lncli.sh --node bob addinvoice --amt=10000 | jq -r '.payment_request')
~/.claude/skills/lnd/scripts/lncli.sh --node alice sendpayment --pay_req=$INVOICE

Multi-Node Ports

Node	P2P Port	gRPC Port	REST Port
alice	9735	10009	8080
bob	9736	10010	8081
charlie	9737	10011	8082

Interop Testing with Eclair

Test channel operations between lnd and eclair:

# Terminal 1: Start eclair stack
cd ~/.claude/skills/eclair/templates
docker-compose up -d
~/.claude/skills/eclair/scripts/regtest-setup.sh

# Terminal 2: Start lnd with shared bitcoind
cd ~/.claude/skills/lnd/templates
docker-compose -f docker-compose-shared.yml up -d --build

# Wait for lnd to sync, then run setup
sleep 10
~/.claude/skills/lnd/scripts/regtest-setup.sh --quick

# Get eclair's pubkey
ECLAIR_PUBKEY=$(docker exec eclair eclair-cli -p devpassword getinfo | jq -r '.nodeId')
echo "Eclair pubkey: $ECLAIR_PUBKEY"

# Connect lnd to eclair
~/.claude/skills/lnd/scripts/lncli.sh connect ${ECLAIR_PUBKEY}@eclair:9735

# Open channel from lnd to eclair
~/.claude/skills/lnd/scripts/lncli.sh openchannel --node_key=$ECLAIR_PUBKEY --local_amt=1000000

# Mine to confirm
~/.claude/skills/eclair/scripts/mine.sh 6

# Check channels on both sides
~/.claude/skills/lnd/scripts/lncli.sh listchannels
docker exec eclair eclair-cli -p devpassword channels

Custom Arguments and Profiles

Pass extra arguments to lnd via LND_EXTRA_ARGS:

# Enable REST API on different port
LND_EXTRA_ARGS="--restlisten=0.0.0.0:8081" docker-compose up -d

# Enable debug logging for specific subsystems
LND_EXTRA_ARGS="--debuglevel=HSWC=trace,PEER=debug" docker-compose up -d

# Multiple extra args
LND_EXTRA_ARGS="--protocol.wumbo-channels --maxchansize=500000000" docker-compose up -d

Build Tags

LND supports various build tags for optional features:

Tag	Description
signrpc	Signing RPC service
walletrpc	Wallet RPC service
chainrpc	Chain RPC service
invoicesrpc	Invoices RPC service
routerrpc	Router RPC service
peersrpc	Peers RPC service
neutrinorpc	Neutrino RPC service
watchtowerrpc	Watchtower RPC service
kvdb_sqlite	SQLite database backend
kvdb_postgres	PostgreSQL database backend
dev	Development features

Build with custom tags:

~/.claude/skills/lnd/scripts/docker-build.sh --tags "signrpc walletrpc routerrpc dev"

Helper Scripts

Script	Description
docker-build.sh	Build lnd image with branch/PR/commit support
docker-start.sh	Start containers with mode selection
docker-stop.sh	Stop containers, optionally clean volumes
lncli.sh	Wrapper for lncli with container and node auto-detection
bitcoin-cli.sh	Wrapper for bitcoin-cli
mine.sh	Mine regtest blocks
regtest-setup.sh	Initialize regtest with funded wallet
multi-node-setup.sh	Initialize multi-node with funded wallets and channels
build-pr.sh	Quick PR build convenience wrapper

Environment Variables

Variable	Description	Default
LND_SOURCE	Path to lnd source directory	/users/roasbeef/gocode/src/github.com/lightningnetwork/lnd
LND_IMAGE	Docker image tag	lnd:local
LND_DEBUG	Log level	debug
LND_EXTRA_ARGS	Additional lnd arguments	(empty)
NETWORK	Bitcoin network	regtest
BACKEND	Backend: bitcoind, btcd, neutrino	bitcoind

Ports

Port	Service	Description
9735	Lightning	Peer-to-peer Lightning protocol
10009	gRPC	LND RPC (for lncli)
8080	REST	REST API
18443	Bitcoin RPC	Bitcoin Core RPC (regtest)
28332	ZMQ	Block notifications
28333	ZMQ	Transaction notifications

Troubleshooting

"transport: Error while dialing dial tcp: connection refused"

• LND is still starting up. Wait a few seconds and retry.
• Check logs: docker logs lnd

"unable to find a path to destination"

• No route to the destination. Check channel balances.
• Run: lncli.sh listchannels to see local/remote balances

Channel stuck in "pending open"

• Mine blocks to confirm: ~/.claude/skills/lnd/scripts/mine.sh 6

"insufficient funds available"

• Check wallet balance: lncli.sh walletbalance
• Fund wallet using regtest-setup.sh

"rpc error: code = Unknown desc = chain backend is still syncing"

• LND is syncing with the blockchain. Wait for sync to complete.
• Check: lncli.sh getinfo and look at synced_to_chain

Build fails with "go: module requires Go X.Y"

• Update Go version or use --prod flag for production Dockerfile

Further Reading

• API Reference - gRPC and REST API documentation
• LND GitHub - Official repository
• LND Documentation - Official docs
• BOLT Specifications - Lightning Network protocol specs