hugomd / lnd-nostr-zapper

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lnd-nostr-zapper

Self-host your own zap server to receive zaps directly to your own Umbrel/LND node!

Heavily inspired by fiatjaf/bridgeaddr and jb55/cln-nostr-zapper.

Features

Implements LUD-06 (LNURLp) and NIP-57.

• Connect to LND via Tor
• Publish zap receipts
• Configure default relays for zap receipts
• Easy deployment with Fly.io
• Public Docker image

Installation

A Docker container image is available via GitHub Container Registry:

docker pull ghcr.io/hugomd/lnd-nostr-zapper:e8de5840

Deploying

Fly.io

Fly makes it easy to run Docker containers, and has a generous free tier.

Install flyctl:

brew install flyctl

Clone this repository:

git clone [e-mail]:hugomd/lnd-nostr-zapper.git && cd lnd-nostr-zapper

Set environment variables

Update the environment variables in fly.toml (e.g. LND_HOST).

Most of the environment variables can be found on your Umbrel node by SSH'ing in and running the commands below:

To find your Tor hostname, run:

cat /home/umbrel/umbrel/tor/data/app-lightning-rest/hostname

LND_HOST should be of the form:

https://TOR_HOSTNAME:8080

To bake a macaroon run:

docker exec lightning_lnd_1 lncli bakemacaroon invoices:read invoices:write

Deploy

Launch the application:

flyctl launch

Set secrets

Set secret values, which will be available to the container as runtime environment variables:

flyctl secrets set NOSTR_KEY="NOSTR_PRIVATE_KEY_HERE"
flyctl secrets set LND_MACAROON="LND_MACAROON_HERE"

This should deploy lnd-nostr-zapper to a fly.dev domain, which you can use to receive zaps! ⚡️

Test!

You can see it in action by running:

flyctl open "/.well-known/lnurlp/capybara"

Configuration

Configuration is done via environment variables:

Environment Variable	Required	Default value	Description
HOST	false	0.0.0.0	The host to bind the HTTP server to.
PORT	false	8080	The port to bind the HTTP server to.
DOMAIN	true	N/A	The domain associated with the server, used in the LNURL callback.
LND_HOST	true	N/A	URL pointing to LND, followed by the REST API port. E.g. https://example.onion:8080
LND_MACAROON	true	N/A	An invoice read/write macaroon for auth with LND.
LND_CERT	false	""	Optional self-signed certificate to call LND. Don't set this if you run Umbrel.
NOSTR_KEY	true	N/A	Nostr private key, used to publish zap receipts.
COMMENT_LENGTH	false	0	Maximum length of associated comments, sent via webhook.
WEBHOOK_URL	false	""	URL to call after successful payment.
DESCRIPTION	false	"Send sats!"	Description shown in LNURL metadata.
IMAGE_URL	false	""	Optional avatar URL shown in LNURL metadata.
RELAYS	false	""	Optional comma separated list of relays to publish zaps to, of the form: wss://relay.damus.io,wss://brb.io.