@erudite-intelligence/x402-xmr

x402 exact payment scheme implementation for Monero (XMR).

First-of-kind x402 implementation for the Monero network.

Architecture Note

Monero cannot sign transactions offline in JS like Bitcoin-family coins. This package uses the monero-wallet-rpc to create transfers and provides the tx_key as cryptographic proof. The server verifies via check_tx_key on the daemon RPC — no wallet needed on the facilitator side.

Install

npm install @erudite-intelligence/x402-xmr

Usage

Client (create payment)

Requires a running monero-wallet-rpc instance:

import { createPayment } from "@erudite-intelligence/x402-xmr";

const paymentHeader = await createPayment({
  walletRpcUrl: "http://127.0.0.1:18082/json_rpc",
  recipientAddress: "4...",
  amount: "0.1",
});
// Set as X-PAYMENT header

Server (verify & settle)

Requires access to a Monero daemon RPC:

import { verifyAndSettle } from "@erudite-intelligence/x402-xmr";

const result = await verifyAndSettle({
  paymentHeader: req.headers["x-payment"],
  expectedRecipient: "4...",
  expectedAmountPiconero: "100000000000",
  daemonRpcUrl: "http://127.0.0.1:18081/json_rpc",
});

if (result.success) {
  console.log("Settled:", result.txHash, "Confirmations:", result.confirmations);
}

How Verification Works

1. Sender creates transfer via wallet RPC → gets tx_hash + tx_key
2. Both are encoded in the X-PAYMENT header
3. Facilitator calls check_tx_key on daemon RPC
4. Daemon cryptographically proves amount sent to address without revealing sender

Security

• Fail-closed: If daemon RPC is unreachable, payment is rejected
• Replay protection: In-memory Map with 1hr TTL (use Redis/DB for multi-instance)
• CAIP-2: monero:mainnet
• No wallet needed on server: Only daemon RPC access required

Author

Erudite Intelligence LLC

License

MIT