x402 Nostr Relay

A Nostr relay that gates EVENT writes behind x402 sBTC micropayments. Reading is free, writing costs sats.

Architecture

• WebSocket (ws://localhost:7777) — Standard NIP-01 relay for subscriptions (REQ, CLOSE). Free.
• HTTP (http://localhost:7778) — x402-gated endpoint for publishing events. Pay sBTC to write.

Quick Start

npm install
npm start

Endpoints

WebSocket (port 7777)

Standard NIP-01 protocol:

• REQ — Subscribe to events (free)
• CLOSE — Close subscription
• EVENT — Submit events (accepted directly over WS for dev/testing)

HTTP (port 7778)

• GET / — Relay info
• POST /api/events — Publish a Nostr event (x402 payment required)

Publishing via HTTP

# First request returns 402 with payment details
curl -X POST http://localhost:7778/api/events \
  -H "Content-Type: application/json" \
  -d '{"id":"...","pubkey":"...","kind":1,"content":"hello","tags":[],"sig":"..."}'

# After paying, include tx proof
curl -X POST http://localhost:7778/api/events \
  -H "Content-Type: application/json" \
  -H "X-Payment-Response: {\"txId\":\"0x...\"}" \
  -d '{"id":"...","pubkey":"...","kind":1,"content":"hello","tags":[],"sig":"..."}'

Pricing

Kind	Cost	Description
0	50 sats	Profile metadata
1	10 sats	Text note
4	5 sats	Encrypted DM
30023	25 sats	Long-form content
Other	10 sats	Default

Payment

Payments are sBTC on Stacks, verified via the Hiro Stacks API.

Pay-to address: SP16H0KE0BPR4XNQ64115V5Y1V3XTPGMWG5YPC9TR

Environment Variables

• WS_PORT — WebSocket port (default: 7777)
• HTTP_PORT — HTTP port (default: 7778)

Testing

npm test

License

MIT