@erudite-intelligence/x402-dot

x402 exact payment scheme implementation for Polkadot DOT.

Part of the EruditePay x402 multi-chain payment infrastructure by Erudite Intelligence LLC.

Overview

This package implements the x402 protocol's exact payment scheme for the Polkadot relay chain. It enables HTTP 402-based micropayments using native DOT transfers via balances.transferKeepAlive.

• CAIP-2 Network ID: polkadot:91b171bb158e2d3848fa23a9f1c25182
• Unit: planck (1 DOT = 10,000,000,000 planck)
• Signing: Sr25519 / Ed25519 via @polkadot/keyring
• Verification: Polkadot RPC + Subscan API

Installation

npm install @erudite-intelligence/x402-dot

Usage

Client — Create a Payment

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

const paymentHeader = await createPayment({
  senderSeed: "bottom drive obey lake curtain smoke basket hold race lonely fit walk",
  recipientAddress: "15oF4uVJwmo4TdGW7VfQxNLavjCXviqWrztPu3cCLCf4B7p",
  amountPlanck: "10000000000",  // 1 DOT
  network: "mainnet",
});

Server — Verify & Settle

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

const result = await verifyAndSettle({
  paymentHeader: req.headers["x-payment"],
  expectedRecipient: "15oF4uVJwmo4TdGW7VfQxNLavjCXviqWrztPu3cCLCf4B7p",
  expectedAmountPlanck: "10000000000",
  network: "mainnet",
});

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

Security

• Replay protection: In-memory Map with 1-hour TTL. Multi-instance deployments MUST use Redis/DB.
• Fail-closed: If balance query or RPC call fails, the payment is REJECTED.
• Mortal transactions: Uses mortal era to enforce transaction expiry on-chain.

License

MIT — Erudite Intelligence LLC