L402 API Catalog › Bitcoin & Lightning Data

LNURL Metadata L402 API

Parse any LNURL or Lightning address into metadata.

30 sats per call, paid over the Lightning Network. No API key and no signup: the first request answers 402 Payment Required with a Lightning invoice, and repeating the request with the proof of payment returns your data.

l402_lnurl_metadata 30 sats

Parameters

lnurl LNURL or Lightning address

Call it with curl

The first call answers 402 with a Lightning invoice in the WWW-Authenticate header. Pay it from any Lightning wallet, then repeat the call with the L402 token and preimage.

cURL

curl -X POST https://lightningfaucet.com/api/ \
  -H "Content-Type: application/json" \
  -H "Authorization: L402 $MACAROON:$PREIMAGE" \
  -d '{"action":"l402_lnurl_metadata","lnurl":"user@domain.com"}'

What comes back

A successful call returns JSON, with the delivered content merged over the standard L402 receipt fields. Example values, not live data.

JSON

{
    "success": true,
    "http_code": 200,
    "service": "lnurl_metadata",
    "timestamp": "2026-09-11T15:04:05+00:00",
    "paid_sats": 30,
    "tag": "payRequest",
    "callback": "https://domain.com/lnurlp/api/v1/lnurl/cb/1",
    "min_sendable_sats": 1,
    "max_sendable_sats": 1000000,
    "metadata": "[[\"text/identifier\",\"user@domain.com\"],[\"text/plain\",\"Pay to user@domain.com\"]]",
    "domain": "domain.com"
}

Call it from an AI agent

With lightning-wallet-mcp the payment is handled for you. From the CLI:

Terminal

lw pay-api "https://lightningfaucet.com/api/l402/lnurl_metadata?lnurl=user%40domain.com"

In Claude Code, Cursor or any MCP host, ask the agent to call pay_l402_api with that URL. The fee is 1% of the price, rounded down, so calls under 100 sats carry no platform fee.

Questions

How much does the LNURL Metadata API cost?
Each call costs 30 sats, paid as a Lightning invoice at request time. There is no subscription, no minimum and no monthly bill: you are charged for the calls you make.

Do I need an API key or an account?
No. Payment is the authentication. The first request answers 402 Payment Required with a Lightning invoice; settling it returns a preimage that authenticates the retry.

What does LNURL Metadata return?
A JSON object carrying tag, callback, min_sendable_sats, max_sendable_sats, metadata and domain. See the example response above for the exact shape.

Related endpoints

Lightning Stats 200 sats Price Oracle 200 sats Invoice Decode 30 sats Node Info 30 sats Fee Estimate 50 sats Ask a Human 500 sats

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