Lnd Emulator Utility · Simple

Mastering the Lightning Network: The Essential Guide to the LND Emulator Utility

Why a Dedicated Utility? (Use Cases)

Before the advent of robust emulation utilities, developers had two choices:

1. Regtest (Regression Test): Spin up a private Bitcoin network with btcd, lnd, and bitcoind. This works but is heavy (multiple containers, slow startup, disk I/O heavy).
2. Unit Tests with Mocks: Mock the LND client at the code level. This is fast but unrealistic—it misses cross-component interactions like HTLC timeouts and fee updates.

The LND emulator utility bridges this gap. Common use cases include: lnd emulator utility

CI Pipeline (GitHub Actions)

- name: Start LND Emulator
  run: |
    ./lnd-emulator --port=10009 &
    sleep 2

name: Run Integration Tests
run: |
go test -v ./... --lnd-host=localhost:10009

Core Components:

• gRPC Server (using grpc-go or grpc-node): Implement the lnd protobuf service.
• In-Memory Store: Golang map or Redis for channels, invoices, and payments.
• State Machine: A simple HTLC simulator with timer goroutines.
• Fake Router: A graph of connected "peers" with channel capacities.

4.2. REST Dashboard (optional)

• Web UI to view channels, invoices, payments
• Manual payment trigger
• Force-close channels / fail HTLCs