arkzap-me

arkzap-me is a small LNURL-pay server for Bark and Arkade. It gives every supported Ark address a deterministic Lightning address, serves LNURL-pay metadata, and generates BOLT11 invoices for incoming payments.

For Bark addresses, the service asks barkd to generate invoices and checks barkd for payment settlement. For Arkade addresses, it uses the Arkade Rust SDK receive-for-user flow to create reverse-swap invoices and claim the resulting VHTLC output to the recipient Arkade address.

Users can also buy custom Lightning address names backed by their Bark Ark address. Ownership is authenticated with Bark address message signatures, and each name activates after its fee invoice is paid to the service Bark wallet.

Invoices, custom names, SDK swap state, and optional Nostr zap requests are persisted in Postgres.

Features

• LNURL-pay metadata at /.well-known/lnurlp/:address
• Invoice generation at /get-invoice/:address
• Bark address support through barkd
• Paid custom Lightning address names for Bark addresses
• Arkade address support through the Arkade SDK receive-for-user branch
• Nostr zaps: validates zap requests and publishes zap receipts once paid
• Postgres persistence through Diesel migrations
• Settlement verification at /verify/:address/:payment_hash

Prerequisites

• Rust toolchain
• Postgres
• Diesel CLI with Postgres support
• A reachable barkd v0.6.2 or later REST API
• A reachable Arkade server
• A reachable Boltz endpoint compatible with Arkade reverse swaps
• An Arkade BIP32 xpriv used to claim reverse-swap VHTLCs
• A Nostr nsec key used to sign zap receipts

Install Diesel CLI if needed:

cargo install diesel_cli --no-default-features --features postgres

Configuration

The binary reads command-line flags and environment variables. It also loads a local .env file on startup.

Variable	Required	Default	Description
LNURL_PG_URL	yes		Postgres connection string used by the application
LNURL_NSEC	yes		Nostr secret key used to sign zap receipts
LNURL_BARKD_URL	yes		Base URL for the barkd REST API
LNURL_BARKD_TOKEN	no		Bearer token for barkd. Required unless barkd uses --no-auth on a loopback address
LNURL_DISABLE_ARKADE	no	false	Disable Arkade address support
LNURL_ARKADE_XPRIV	yes, unless Arkade is disabled		BIP32 xpriv used by the Arkade SDK to claim reverse-swap VHTLCs
LNURL_ARKADE_SERVER_URL	yes, unless Arkade is disabled		Arkade server URL used by the Arkade SDK
LNURL_ARKADE_BOLTZ_URL	yes, unless Arkade is disabled		Boltz URL used by the Arkade SDK
LNURL_ARKADE_ESPLORA_URL	no	https://mempool.space/api	Esplora URL used by the Arkade SDK wallet implementation
LNURL_ARKADE_INVOICE_EXPIRY_SECS	no		Optional Arkade-generated invoice expiry in seconds
LNURL_BIND	no	0.0.0.0	HTTP bind address
LNURL_PORT	no	3000	HTTP port
LNURL_NETWORK	no	bitcoin	Bitcoin network
LNURL_MIN_SENDABLE	no	1000	Minimum LNURL amount in millisatoshis
LNURL_MAX_SENDABLE	no	11000000000	Maximum LNURL amount in millisatoshis

Arkade addresses require a minimum amount of 333000 millisatoshis.

Bark v0.6.2 does not read BARKD_NO_AUTH.

If barkd listens on a loopback address, start it with --no-auth. For all other deployments, set LNURL_BARKD_TOKEN to the bearer token from barkd.

Example .env:

LNURL_PG_URL=postgres://postgres:[email protected]:5432/arkzap_me
LNURL_NSEC=nsec...
LNURL_BARKD_URL=http://127.0.0.1:3535
LNURL_BARKD_TOKEN=
LNURL_ARKADE_XPRIV=xprv...
LNURL_ARKADE_SERVER_URL=http://127.0.0.1:7070
LNURL_ARKADE_BOLTZ_URL=http://127.0.0.1:9001
LNURL_ARKADE_ESPLORA_URL=http://127.0.0.1:3002
LNURL_DOMAIN=example.com
LNURL_PORT=3000

Set LNURL_DISABLE_ARKADE=true or pass --disable-arkade to run with Bark-only address support. Arkade addresses will be rejected and the Arkade SDK client will not be initialized.

For Diesel CLI commands, also set DATABASE_URL to the same Postgres URL:

export DATABASE_URL="$LNURL_PG_URL"

Database Setup

Create the database, then run migrations:

createdb arkzap_me
diesel migration run

The migrations create Bark invoice/zap tables, Arkade invoice/zap tables, and an Arkade SDK swap-storage table.

Running

cargo run

By default the server listens on 0.0.0.0:3000.

You can also pass configuration as flags:

cargo run -- \
  --pg-url postgres://postgres:[email protected]:5432/arkzap_me \
  --nsec nsec... \
  --barkd-url http://127.0.0.1:3535 \
  --arkade-xpriv xprv... \
  --arkade-server-url http://127.0.0.1:7070 \
  --arkade-boltz-url http://127.0.0.1:9001 \
  --domain example.com

For Bark-only mode, omit the Arkade options and pass --disable-arkade.

NixOS

The flake provides the server package, a development shell, and a NixOS module. Import the module from your system flake and enable the service:

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