Lightning Charge

A drop-in solution for accepting lightning payments, built on top of c-lightning.

Simple HTTP REST API, optimized for developer friendliness and ease of integration. Near-zero configuration.
Supports invoice metadata, fiat currency conversion, long polling, web hooks, websockets and server-sent-events.
Built-in checkout page, can be iframed or redirected to.

⚡ radically low fees ⚡ nano payments ⚡ instant confirmations ⚡

Getting Started

Setup c-lightning and nodejs (v7.6 or newer), then:

$ npm install -g lightning-charge

$ charged --api-token mySecretToken # defaults: --ln-path ~/.lightning --db-path ./charge.db --port 9112

# configuration options may alternatively be provided using environment variables:
$ LN_PATH=~/.lightning DB_PATH=charge.db API_TOKEN=mySecretToken PORT=9112 charged

Your chosen --api-token will be used to authenticate requests made to the Lightning Charge REST API.

See $ charged --help for the full list of available options.

Docker

Deploy with docker, comes bundled with bitcoind+lightningd+charged:

$ mkdir data # make sure to create the folder _before_ running docker
$ docker run -u `id -u` -v `pwd`/data:/data -p 9112:9112 \
             -e API_TOKEN=mySecretToken \
             shesek/lightning-charge

Runs in testnet mode by default, set NETWORK to override.

If you want to experiment in regtest mode and don't care about persisting data, this should do:

$ docker run -e NETWORK=regtest -e API_TOKEN=mySecretToken -p 9112:9112 shesek/lightning-charge

Client libraries

Clients libraries are available for JavaScript and PHP. For other languages, you can use the REST API directly using a standard HTTP library.

REST API

All endpoints accept and return data in JSON format.

Authentication is done using HTTP basic authentication headers, with api-token as the username and the api token (configured with --api-token/-t or using the API_TOKEN environment variable) as the password.

Invoices have the following properties: id, msatoshi, quoted_currency, quoted_amount, rhash, payreq, description, created_at, expires_at, paid_at, metadata and status (one of unpaid|paid|expired).

The completed (replaced with status) and completed_at (renamed to paid_at) fields are deprecated, but currently still available. They will eventually be removed.

The code samples below assumes you've set CHARGE=http://api-token:mySecretToken@localhost:9112.

`POST /invoice`

Create a new invoice.

Body parameters: msatoshi, currency, amount, description, expiry and metadata.

You can specify the amount as msatoshi (1 satoshi = 1000 msatoshis), or provide a currency and amount to be converted according to the current exchange rates. If a currency and amount were provided, they'll be available under quoted_{currency|amount}.

expiry sets the invoice expiry time in seconds (defaults to one hour). metadata may contain arbitrary invoice-related meta-data. description is embedded in the payment request and presented by the user's wallet (keep it short).

Returns 201 Created and the invoice on success.

$ curl $CHARGE/invoice -d msatoshi=10000
{"id":"KcoQHfHJSx3fVhp3b1Y3h","msatoshi":"10000","status":"unpaid","rhash":"6823e46a08f50...",
 "payreq":"lntb100n1pd99d02pp...","created_at":1515369962,"expires_at":1515373562}

# with fiat-denominated amounts
$ curl $CHARGE/invoice -d currency=EUR -d amount=0.5
{"id":"OYwwaOQAPMFvg039gj_Rb","msatoshi":"3738106","quoted_currency":"EUR","quoted_amount":"0.5",...}

# with metadata as application/json
$ curl $CHARGE/invoice -H 'Content-Type: application/json' \
  -d '{"msatoshi":7000,"metadata":{"customer_id":9817,"products":[593,182]}}'
{"id":"PLKV1f8B7sth7w2OeDOt_","msatoshi":"7000","metadata":{"customer_id":9817,"products":[593,182]},...}

# with metadata as application/x-www-form-urlencoded
$ curl $CHARGE/invoice -d msatoshi=5000 -d metadata[customer_id]=9817 -d metadata[product_id]=7189
{"id":"58H9eoerBpKML9FvnMQtG","msatoshi":"5000","metadata":{"customer_id":"9817","product_id":"7189"},...}

`GET /invoices`

List all invoices.

$ curl $CHARGE/invoices
[{"id":"KcoQHfHJSx3fVhp3b1Y3h","msatoshi":"10000",...},{"id":"PLKV1f8B7sth7w2OeDOt_","msatoshi":"7000"},...]

`GET /invoice/:id`

Get the specified invoice.

$ curl $CHARGE/invoice/OYwwaOQAPMFvg039gj_Rb
{"id":"OYwwaOQAPMFvg039gj_Rb","msatoshi":"3738106","quoted_currency":"EUR","quoted_amount":"0.5","status":"unpaid",...}

`GET /invoice/:id/wait?timeout=[sec]`

Long-polling invoice payment notification.

Waits for the invoice to be paid, then returns 200 OK and the updated invoice.

If timeout (defaults to 30s) is reached before the invoice is paid, returns 402 Payment Required.

If the invoice is expired and can no longer be paid, returns 410 Gone.

$ curl $CHARGE/invoice/OYwwaOQAPMFvg039gj_Rb/wait?timeout=60
# zZZZzzZ
{"id":"OYwwaOQAPMFvg039gj_Rb","msatoshi":"3738106","status":"paid","paid_at":1515371152,...}

`POST /invoice/:id/webhook`

Body parameters: url.

Returns 201 Created on success. Once the payment is made, a POST request with the updated invoice will be made to the provided URL.

If the invoice is already paid, returns 405 Method Not Allowed. If the invoice is expired, returns 410 Gone.

For security reasons, the provided url should contain a secret token used to verify the authenticity of the request (see an example HMAC-based implementation at woocommerce-gateway-lightning here, here and here).

$ curl $CHARGE/invoice/OYwwaOQAPMFvg039gj_Rb/webhook -d url=http://example.com/callback
Created

`GET /payment-stream`

Subscribe to payment updates as a server-sent events stream.

$ curl $CHARGE/payment-stream
# zzZZzZZ
data:{"id":"OYwwaOQAPMFvg039gj_Rb","msatoshi":"3738106","status":"paid","paid_at":1515371152,...}
# zZZzzZz
data:{"id":"KcoQHfHJSx3fVhp3b1Y3h","msatoshi":"10000","status":"paid","paid_at":1515681209,...}
# zZZzzzz...

WebSocket API

`GET /ws`

Subscribe to payment updates over WebSocket.

const ws = new WebSocket('http://api-token:[TOKEN]@charge.ln/ws')

ws.on('message', msg => {
  const inv = JSON.parse(msg)
  console.log('Paid invoice:', inv)
})

Tests

Make sure bitcoind, bitcoin-cli, lightningd, lightning-cli and jq are in your PATH, then run $ npm test. This will setup a temporary testing environment with a bitcoind regtest node and two c-lightning nodes with a funded channel, then start the Lightning Charge server and run the unit tests (written with mocha and supertest).

To run in verbose mode, set the VERBOSE environment variable: $ VERBOSE=1 npm test.

To pass arguments to mocha, use $ npm test -- [mocha opts].

To prevent the test environment files from being deleted after completing the tests, set KEEP_TMPDIR=1.

To setup a testing environment without running the tests, run $ npm run testenv. This will display information about the running services and keep them alive for further inspection.

Tests can also be run using docker: $ docker run shesek/lightning-charge npm test

License

MIT

NicolasDorier / lightning-charge