Core Lightning (CLN): A specification compliant Lightning Network implementation in C
Core Lightning (previously c-lightning) is a lightweight, highly customizable and standard compliant implementation of the Lightning Network protocol, developed and maintained by Blockstream. Learn more about Blockstream's Lightning Network updates at blockstream.com/lightning.
Project Status
This implementation has been in production use on the Bitcoin mainnet since early 2018, with the launch of the Blockstream Store.
We recommend getting started by experimenting on testnet (testnet4 or regtest), but the implementation is considered stable and can be safely used on mainnet.
Reach Out to Us
Any help testing the implementation, reporting bugs, or helping with outstanding issues is very welcome.
Don't hesitate to reach out to us on CLN Discord, or on CLN Telegram.
Getting Started
Core Lightning only works on Linux and macOS, and requires a locally (or remotely) running bitcoind (version 25.0 or above) that is fully caught up with the network you're running on, and relays transactions (ie with blocksonly=0).
Pruning (prune=n option in bitcoin.conf) is partially supported, see here for more details.
Installation
There are 3 supported installation options:
Starting lightningd
Regtest (local, fast-start) Option
If you want to experiment with lightningd, there's a script to set
up a bitcoind regtest test network of two local lightning nodes,
which provides a convenient start_ln helper. See the notes at the top
of the startup_regtest.sh file for details on how to use it.
. contrib/startup_regtest.sh
Mainnet Option
To test with real bitcoin, you will need to have a local bitcoind node running:
bitcoind -daemon
Wait until bitcoind has synchronized with the network.
Make sure that you do not have walletbroadcast=0 in your ~/.bitcoin/bitcoin.conf, or you may run into trouble.
Notice that running lightningd against a pruned node may cause some issues if not managed carefully, see below for more information.
You can start lightningd with the following command:
lightningd --network=bitcoin --log-level=debug
This creates a .lightning/ subdirectory in your home directory: see man -l doc/lightningd.8 (or https://docs.corelightning.org/docs) for more runtime options.
Using The JSON-RPC Interface
Core Lightning exposes a JSON-RPC 2.0 interface over a Unix Domain socket; the lightning-cli tool can be used to access it, or there is a python client library.
You can use lightning-cli help to print a table of RPC methods; lightning-cli help <command>
will offer specific information on that command.
Useful commands:
- newaddr: get a bitcoin address to deposit funds into your lightning node.
- listfunds: see where your funds are.
- connect: connect to another lightning node.
- fundchannel: create a channel to another connected node.
- invoice: create an invoice to get paid by another node.
- xpay: pay someone else's invoice.
- plugin: commands to control extensions.
Care And Feeding Of Your New Lightning Node
Once you've started for the first time, there's a script called
contrib/bootstrap-node.sh which will connect you to other nodes on
the lightning network.
There are also numerous plugins available for Core Lightning which add
capabilities: in particular there's a collection at: https://github.com/lightningd/plugins
For a less reckless experience, you can encrypt the HD wallet seed:
see HD wallet encryption.
You can also chat to other users at Discord core-lightning;
we are always happy to help you get started!
Opening A Channel
First you need to transfer some funds to lightningd so that it can
open a channel:
# Returns an address <address>
lightning-cli newaddr
lightningd will register the funds once the transaction is confirmed.
Alternatively you can generate a taproot address should your source of funds support it:
# Return a taproot address
lightning-cli newaddr p2tr
Confirm lightningd got funds by:
# Returns an array of on-chain funds.
lightning-cli listfunds
This is the beginning of the README. Read the rest at the original. Read the full README ↗
