![Eclair Logo](.readme/logo.png) [![Build Status](https://travis-ci.org/ACINQ/eclair.svg?branch=master)](https://travis-ci.org/ACINQ/eclair) [![codecov](https://codecov.io/gh/acinq/eclair/branch/master/graph/badge.svg)](https://codecov.io/gh/acinq/eclair) [![License](https://img.shields.io/badge/license-Apache%202.0-blue.svg)](LICENSE) [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-red.svg)](https://gitter.im/ACINQ/eclair) **Eclair** (French for Lightning) is a Scala implementation of the Lightning Network. It can run with or without a GUI, and a JSON API is also available. This software follows the [Lightning Network Specifications (BOLTs)](https://github.com/lightningnetwork/lightning-rfc). Other implementations include [c-lightning](https://github.com/ElementsProject/lightning) and [lnd](https://github.com/LightningNetwork/lnd). --- :construction: Both the BOLTs and Eclair itself are still a work in progress. Expect things to break/change! :rotating_light: If you run Eclair on mainnet (which is the default setting): * Keep in mind that it is beta-quality software and **don't put too much money** in it * Eclair's JSON API should **NOT** be accessible from the outside world (similarly to Bitcoin Core API) --- ## Lightning Network Specification Compliance Please see the latest [release note](https://github.com/ACINQ/eclair/releases) for detailed information on BOLT compliance. ## Overview ![Eclair Demo](.readme/screen-1.png) ## JSON API Eclair offers a feature rich HTTP API that enables application developers to easily integrate. For more information please visit the [API documentation website](https://acinq.github.io/eclair). ## Documentation Please visit our [wiki](https://github.com/acinq/eclair/wiki) to find detailed instructions on how to configure your node, connect to other nodes, open channels, send and receive payments and more advanced scenario. You will find detailed guides and frequently asked questions there. ## Installation ### Configuring Bitcoin Core :warning: Eclair requires Bitcoin Core 0.17.1 or higher. If you are upgrading an existing wallet, you need to create a new address and send all your funds to that address. Eclair needs a _synchronized_, _segwit-ready_, **_zeromq-enabled_**, _wallet-enabled_, _non-pruning_, _tx-indexing_ [Bitcoin Core](https://github.com/bitcoin/bitcoin) node. Eclair will use any BTC it finds in the default Bitcoin Core wallet to fund any channels you choose to open. Eclair will return BTC from closed channels to this wallet. You can have multiple Bitcoin Core wallets but make sure that the default one is always available. Any BTC found in the wallet can be used to fund the channels you choose to open and the BTC from closed channels will return to this wallet. You can configure your Bitcoin Node to use either `p2sh-segwit` addresses or `bech32` addresses, Eclair is compatible with both modes. If your Bitcoin Core wallet has "non-segwit UTXOs" (outputs that are neither `p2sh-segwit` or `bech32`), you must send them to a `p2sh-segwit` or `bech32` address. Run bitcoind with the following minimal `bitcoin.conf`: ```conf server=1 rpcuser=foo rpcpassword=bar txindex=1 zmqpubrawblock=tcp://127.0.0.1:29000 zmqpubrawtx=tcp://127.0.0.1:29000 ``` ### Installing Eclair Eclair is developed in [Scala](https://www.scala-lang.org/), a powerful functional language that runs on the JVM, and is packaged as a ZIP archive. We provide 2 different packages, which internally use the same core libraries: * eclair-node, which is a headless application that you can run on servers and desktops, and control from the command line * eclair-node-gui, which also includes a JavaFX GUI To run Eclair, you first need to install Java, we recommend that you use [OpenJDK 11](https://adoptopenjdk.net/?variant=openjdk11&jvmVariant=hotspot). Other runtimes also work but we don't recommend using them. Then download our latest [release](https://github.com/ACINQ/eclair/releases), unzip the archive and depending on whether or not you want a GUI run the following command: * with GUI: ```shell eclair-node-gui--/bin/eclair-node-gui.sh ``` * without GUI: ```shell eclair-node--/bin/eclair-node.sh ``` ### Configuring Eclair #### Configuration file Eclair reads its configuration file, and write its logs, to `~/.eclair` by default. To change your node's configuration, create a file named `eclair.conf` in `~/.eclair`. Here's an example configuration file: ```conf eclair.node-alias=eclair eclair.node-color=49daaa ``` Here are some of the most common options: name | description | default value -----------------------------|---------------------------------------------------------------------------------------|-------------- eclair.chain | Which blockchain to use: *regtest*, *testnet* or *mainnet* | mainnet eclair.server.port | Lightning TCP port | 9735 eclair.api.enabled | Enable/disable the API | false. By default the API is disabled. If you want to enable it, you must set a password. eclair.api.port | API HTTP port | 8080 eclair.api.password | API password (BASIC) | "" (must be set if the API is enabled) eclair.bitcoind.rpcuser | Bitcoin Core RPC user | foo eclair.bitcoind.rpcpassword | Bitcoin Core RPC password | bar eclair.bitcoind.zmqblock | Bitcoin Core ZMQ block address | "tcp://127.0.0.1:29000" eclair.bitcoind.zmqtx | Bitcoin Core ZMQ tx address | "tcp://127.0.0.1:29000" eclair.gui.unit | Unit in which amounts are displayed (possible values: msat, sat, bits, mbtc, btc) | btc Quotes are not required unless the value contains special characters. Full syntax guide [here](https://github.com/lightbend/config/blob/master/HOCON.md). → see [`reference.conf`](eclair-core/src/main/resources/reference.conf) for full reference. There are many more options! #### Java Environment Variables Some advanced parameters can be changed with java environment variables. Most users won't need this and can skip this section. :warning: Using separate `datadir` is mandatory if you want to run **several instances of eclair** on the same machine. You will also have to change ports in `eclair.conf` (see above). name | description | default value ----------------------|--------------------------------------------|-------------- eclair.datadir | Path to the data directory | ~/.eclair eclair.headless | Run eclair without a GUI | eclair.printToConsole | Log to stdout (in addition to eclair.log) | For example, to specify a different data directory you would run the following command: ```shell eclair-node--/bin/eclair-node.sh -Declair.datadir=/tmp/node1 ``` #### Logging Eclair uses [`logback`](https://logback.qos.ch) for logging. To use a different configuration, and override the internal logback.xml, run: ```shell eclair-node--/bin/eclair-node.sh -Dlogback.configurationFile=/path/to/logback-custom.xml ``` #### Backup The files that you need to backup are located in your data directory. You must backup: * your seed (`seed.dat`) * your channel database (`eclair.sqlite.bak` under directory `mainnet`, `testnet` or `regtest` depending on which chain you're running on) Your seed never changes once it has been created, but your channels will change whenever you receive or send payments. Eclair will create and maintain a snapshot of its database, named `eclair.sqlite.bak`, in your data directory, and update it when needed. This file is always consistent and safe to use even when Eclair is running, and this is what you should backup regularly. For example you could configure a `cron` task for your backup job. Or you could configure an optional notification script to be called by eclair once a new database snapshot has been created, using the following option: ```conf eclair.backup-notify-script = "/absolute/path/to/script.sh" ``` Make sure that your script is executable and uses an absolute path name for `eclair.sqlite.bak`. Note that depending on your filesystem, in your backup process we recommend first moving `eclair.sqlite.bak` to some temporary file before copying that file to your final backup location. ## Docker A [Dockerfile](Dockerfile) image is built on each commit on [docker hub](https://hub.docker.com/r/acinq/eclair) for running a dockerized eclair-node. You can use the `JAVA_OPTS` environment variable to set arguments to `eclair-node`. ```shell docker run -ti --rm -e "JAVA_OPTS=-Xmx512m -Declair.api.binding-ip=0.0.0.0 -Declair.node-alias=node-pm -Declair.printToConsole" acinq/eclair ``` If you want to persist the data directory, you can make the volume to your host with the `-v` argument, as the following example: ```shell docker run -ti --rm -v "/path_on_host:/data" -e "JAVA_OPTS=-Declair.printToConsole" acinq/eclair ``` If you enabled the API you can check the status of eclair using the command line tool: ```shell docker exec eclair-cli -p foobar getinfo ``` ## Plugins For advanced usage, Eclair supports plugins written in Scala, Java, or any JVM-compatible language. A valid plugin is a jar that contains an implementation of the [Plugin](eclair-node/src/main/scala/fr/acinq/eclair/Plugin.scala) interface, and a manifest entry for `Main-Class` with the FQDN of the implementation. Here is how to run Eclair with plugins: ```shell eclair-node--/bin/eclair-node.sh <...> ``` ## Testnet usage Eclair is configured to run on mainnet by default, but you can still run it on testnet (or regtest): start your Bitcoin Node in testnet mode (add `testnet=1` in `bitcoin.conf` or start with `-testnet`), and change Eclair's chain parameter and Bitcoin RPC port: ```conf eclair.chain=testnet eclair.bitcoind.rpcport=18332 ``` You may also want to take advantage of the new configuration sections in `bitcoin.conf` to manage parameters that are network specific, so you can easily run your bitcoin node on both mainnet and testnet. For example you could use: ```conf server=1 txindex=1 [main] rpcuser= rpcpassword= zmqpubrawblock=tcp://127.0.0.1:29000 zmqpubrawtx=tcp://127.0.0.1:29000 [test] rpcuser= rpcpassword= zmqpubrawblock=tcp://127.0.0.1:29001 zmqpubrawtx=tcp://127.0.0.1:29001 ``` ## Resources * [1] [The Bitcoin Lightning Network: Scalable Off-Chain Instant Payments](https://lightning.network/lightning-network-paper.pdf) by Joseph Poon and Thaddeus Dryja * [2] [Reaching The Ground With Lightning](https://github.com/ElementsProject/lightning/raw/master/doc/deployable-lightning.pdf) by Rusty Russell * [3] [Lightning Network Explorer](https://explorer.acinq.co) - Explore testnet LN nodes you can connect to