![Eclair Logo](.readme/logo.png)

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**Eclair** (French for Lightning) is a Scala implementation of the Lightning Network. It can run with or without a GUI, and a JSON-RPC 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 intend to run Eclair on mainnet:
 - Keep in mind that it is beta-quality software and **don't put too much money** in it
 - Eclair's JSON-RPC API should **NOT** be accessible from the outside world (similarly to Bitcoin Core API)
 - Specific [configuration instructions for mainnet](#mainnet-usage) are provided below (by default Eclair runs on testnet)
 
---

## 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)

## Installation

### Configuring Bitcoin Core

:warning: Eclair requires Bitcoin Core 0.16.3 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 Bitcoin Core wallet to fund any channels you choose to open. Eclair will return BTC from closed channels to this wallet.

Run bitcoind with the following minimal `bitcoin.conf`:
```
testnet=1
server=1
rpcuser=foo
rpcpassword=bar
txindex=1
zmqpubrawblock=tcp://127.0.0.1:29000
zmqpubrawtx=tcp://127.0.0.1:29000
addresstype=p2sh-segwit
```

:warning: If you are using Bitcoin Core 0.17.0 you need to add following line to your `bitcoin.conf`:
```
deprecatedrpc=signrawtransaction
```

### Installing Eclair

The released binaries can be downloaded [here](https://github.com/ACINQ/eclair/releases).

#### Windows

Just use the windows installer, it should create a shortcut on your desktop.

#### Linux, macOS or manual install on Windows

You need to first install java, more precisely a [JRE 1.8](http://www.oracle.com/technetwork/java/javase/downloads/jre8-downloads-2133155.html).

 :warning: If you are using the OpenJDK JRE, you will need to build OpenJFX yourself, or run the application in headless mode (see below).

Then download the latest fat jar and depending on whether or not you want a GUI run the following command:
* with GUI:
```shell
java -jar eclair-node-gui-<version>-<commit_id>.jar
```
* without GUI:
```shell
java -jar eclair-node-<version>-<commit_id>.jar
```

### 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:

```
eclair.chain=testnet
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*                            | testnet
 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, 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).

&rarr; 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
java -Declair.datadir=/tmp/node1 -jar eclair-node-gui-<version>-<commit_id>.jar
```

#### Logging

Eclair uses [`logback`](https://logback.qos.ch) for logging. To use a different configuration, and override the internal logback.xml, run:

```shell
java -Dlogback.configurationFile=/path/to/logback-custom.xml -jar eclair-node-gui-<version>-<commit_id>.jar
```

## JSON-RPC API

 method        |  params                                                                                | description
 ------------- |----------------------------------------------------------------------------------------|-----------------------------------------------------------
  getinfo      |                                                                                        | return basic node information (id, chain hash, current block height) 
  connect      | nodeId, host, port                                                                     | open a secure connection to a lightning node
  connect      | uri                                                                                    | open a secure connection to a lightning node
  open         | nodeId, fundingSatoshis, pushMsat = 0, feerateSatPerByte = ?, channelFlags = 0x01      | open a channel with another lightning node, by default push = 0, feerate for the funding tx targets 6 blocks, and channel is announced
  updaterelayfee | channelId, feeBaseMsat, feeProportionalMillionths                                    | update relay fee for payments going through this channel
  peers        |                                                                                        | list existing local peers
  channels     |                                                                                        | list existing local channels
  channels     | nodeId                                                                                 | list existing local channels opened with a particular nodeId
  channel      | channelId                                                                              | retrieve detailed information about a given channel
  channelstats |                                                                                        | retrieves statistics about channel usage (fees, number and average amount of payments)
  allnodes     |                                                                                        | list all known nodes
  allchannels  |                                                                                        | list all known channels
  allupdates   |                                                                                        | list all channels updates
  allupdates   | nodeId                                                                                 | list all channels updates for this nodeId
  receive      | description                                                                            | generate a payment request without a required amount (can be useful for donations)
  receive      | amountMsat, description                                                                | generate a payment request for a given amount
  receive      | amountMsat, description, expirySeconds                                                 | generate a payment request for a given amount that expires after given number of seconds
  checkinvoice | paymentRequest                                                                         | returns node, amount and payment hash in an invoice/paymentRequest
  findroute    | paymentRequest|nodeId                                                                  | given a payment request or nodeID checks if there is a valid payment route returns JSON with attempts, nodes and channels of route
  send         | amountMsat, paymentHash, nodeId                                                        | send a payment to a lightning node
  send         | paymentRequest                                                                         | send a payment to a lightning node using a BOLT11 payment request
  send         | paymentRequest, amountMsat                                                             | send a payment to a lightning node using a BOLT11 payment request and a custom amount
  checkpayment | paymentHash                                                                            | returns true if the payment has been received, false otherwise
  checkpayment | paymentRequest                                                                         | returns true if the payment has been received, false otherwise
  close        | channelId                                                                              | close a channel
  close        | channelId, scriptPubKey                                                                | close a channel and send the funds to the given scriptPubKey
  forceclose   | channelId                                                                              | force-close a channel by publishing the local commitment tx (careful: this is more expensive than a regular close and will incur a delay before funds are spendable)"
  audit        |                                                                                        | list all send/received/relayed payments
  audit        | from, to                                                                               | list send/received/relayed payments in that interval (from <= timestamp < to)
  networkfees  |                                                                                        | list all network fees paid to the miners, by transaction
  networkfees  |from, to                                                                                | list network fees paid to the miners, by transaction, in that interval (from <= timestamp < to)
  help         |                                                                                        | display available methods

## 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`.

```
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:

```
docker run -ti --rm -v "/path_on_host:/data" -e "JAVA_OPTS=-Declair.printToConsole" acinq/eclair
```

## Mainnet usage

Following are the minimum configuration files you need to use for Bitcoin Core and Eclair.

### Bitcoin Core configuration

```
testnet=0
server=1
rpcuser=<your-rpc-user-here>
rpcpassword=<your-rpc-password-here>
txindex=1
zmqpubrawblock=tcp://127.0.0.1:29000
zmqpubrawtx=tcp://127.0.0.1:29000
addresstype=p2sh-segwit
```

:warning: If you are using Bitcoin Core 0.17.0 you need to add following line to your `bitcoin.conf`:
```
deprecatedrpc=signrawtransaction
```

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:

```
server=1
txindex=1
addresstype=p2sh-segwit
deprecatedrpc=signrawtransaction
[main]
rpcuser=<your-mainnet-rpc-user-here>
rpcpassword=<your-mainnet-rpc-password-here>
zmqpubrawblock=tcp://127.0.0.1:29000
zmqpubrawtx=tcp://127.0.0.1:29000
[test]
rpcuser=<your-testnet-rpc-user-here>
rpcpassword=<your-testnet-rpc-password-here>
zmqpubrawblock=tcp://127.0.0.1:29001
zmqpubrawtx=tcp://127.0.0.1:29001
```

### Eclair configuration

```
eclair.chain=mainnet
eclair.bitcoind.rpcport=8332
eclair.bitcoind.rpcuser=<your-mainnet-rpc-user-here>
eclair.bitcoind.rpcpassword=<your-mainnet-rpc-password-here>
```

## 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