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.

:zap: radically low fees :zap: nano payments :zap: instant confirmations :zap:

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/testnet --db-path ./charge.db --port 9112

Note: if you're running into permission issues, try following these instructions.

That's it! The Lightning Charge REST API is now running and ready to process payments. You can access it at http://localhost:9112 using the API access token configured with --api-token.

Configuration options may alternatively be provided using environment variables:

$ LN_PATH=~/.lightning/testnet DB_PATH=charge.db API_TOKEN=mySecretToken PORT=9112 charged

Listens for connections on 127.0.0.1 by default. Set -i 0.0.0.0 to bind on all available interfaces. Note that Charge does not have TLS encryption and should not normally be exposed directly to the public internet. For remote access, you should setup an SSH tunnel or a TLS-enabled reverse proxy like nginx.

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

Deploy with Docker

To deploy Lightning Charge with Docker, run these commands:

$ mkdir data # make sure to create the folder _before_ running docker
$ docker run -it -u `id -u` -v `pwd`/data:/data -p 9735:9735 -p 9112:9112 \
             shesek/lightning-charge --api-token mySecretToken

This will start bitcoind, lightningd and charged and hook them up together. You will then be able to access the REST API at http://localhost:9112 using mySecretToken.

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 -it -e NETWORK=regtest -p 9112:9112 shesek/lightning-charge --api-token mySecretToken

To connect to an existing lightningd instance running on the same machine, mount the lightning data directory to /etc/lightning (e.g. -v $HOME/.lightning:/etc/lightning). Connecting to remote lightningd instances is currently not supported.

To connect to an existing bitcoind instance running on the same machine, mount the bitcoin data directory to /etc/bitcoin (e.g. -v $HOME/.bitcoin:/etc/bitcoin). To connect to a remote bitcoind instance, set BITCOIND_URI=http://[user]:[pass]@[host]:[port] (or use __cookie__:... as the login for cookie-based authentication).

Deploy to Azure

One-click deployment on Azure (by @NicolasDorier).

An instructional video is available here.

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.

LApps

Below are example LApps built on top of Lightning Charge:

• FileBazaar: an ecommerce tool for content creators that produce digital files like photos, videos, or music.

• Lightning Publisher: accept bitcoin payments for content on WordPress blogs.

• nanotip: a simple web server for accepting lightning donations (a lightning tip jar).

• paypercall: easily charge for HTTP APIs on a pay-per-call basis.

• nanopos: a simple point-of-sale system for physical stores.

• ifpaytt: trigger IFTTT actions with lightning payments.

• WooCommerce Lightning: a lightning gateway for the WooCommerce e-commerce software.

• Lightning Jukebox: a lightning powered jukebox. Pay with Bitcoin to choose your music.

Third party Lapps:

• Satoshi's Place: a collaborative art board, pay with lightning to draw on a pixel grid. (live on satoshis.place)

• Pollo feed: a lightning powered chicken feeder. (live on pollofeed.com)

• lightning-captive-portal: Wi-Fi access through a nodogsplash captive portal with Lightning payments.

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, msatoshi_received, quoted_currency, quoted_amount, rhash, payreq, description, created_at, expires_at, paid_at, metadata and status (one of unpaid|paid|expired).

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

GET /info

Get information about the c-lightning node.

$ curl $CHARGE/info
{"id":"032c6ba19a2141c5fee6ac8b6ff6cf24456fd4e8e206716a39af3300876c3a4835","port":42259,"address":[],"version":"v0.5.2-2016-11-21-1937-ge97ee3d","blockheight":434,"network":"regtest"}

POST /invoice

Create a new invoice.

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

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 (via bitcoinaverage). 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).

webhook may contain a URL to be registered as a webhook (see POST /invoice/:id/webhook).

Returns 201 Created and the invoice on success.

$ curl -X POST $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 -X POST $CHARGE/invoice -d currency=EUR -d amount=0.5
{"id":"OYwwaOQAPMFvg039gj_Rb","msatoshi":"3738106","quoted_currency":"EUR","quoted_amount":"0.5",...}

# without amount (accept all payments)
$ curl -X POST $CHARGE/invoice
{"id":"W8CF0UqY7qfAHCfnchqk9","msatoshi":null,...}

# with metadata as application/json
$ curl -X POST $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 -X POST $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",...}

DELETE /invoice/:id

Delete the specified invoice.

Body parameters: status

The current status of the invoice needs to be specified in the request body.

$ curl -X DELETE $CHARGE/invoice/OYwwaOQAPMFvg039gj_Rb -d status=unpaid
204 No Content

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

Register a URL as a web hook to be notified once the invoice is paid.

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.

Webhooks can also be registered during invoice creation using the webhook parameter.

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 -X POST $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...

Or via JavaScript:

const es = new EventSource('http://api-token:[TOKEN]@localhost:9112/payment-stream')

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

(EventSource is natively available in modern browsers, or via the eventsource library in nodejs)

WebSocket API

GET /ws

Subscribe to payment updates over WebSocket.

const ws = new WebSocket('http://api-token:[TOKEN]@localhost:9112/ws')

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

Tests

Requires bitcoind, bitcoin-cli, lightningd, lightning-cli and jq to be in your PATH.

$ git clone https://github.com/ElementsProject/lightning-charge.git
$ cd lightning-charge
$ npm install
$ 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 build --build-arg TESTRUNNER=1 -t charge . && docker run -it --entrypoint npm charge test

License

MIT