@erudite-intelligence/x402-ftm

x402 exact payment scheme implementation for Fantom/Sonic FTM.

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 Fantom Opera and Sonic networks. Standard EVM-compatible native FTM transfers using ethers.js.

• CAIP-2 Network ID: eip155:250 (Opera) / eip155:146 (Sonic)
• Unit: wei (1 FTM = 10^18 wei)
• Signing: ECDSA secp256k1 via ethers.js
• Verification: EVM RPC (Ankr, Fantom public, Sonic)
• Tx type: EIP-1559

Installation

npm install @erudite-intelligence/x402-ftm

Usage

Client — Create a Payment

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

const paymentHeader = await createPayment({
  senderPrivateKey: "0xabc123...",
  recipientAddress: "0xdef456...",
  amountWei: "1000000000000000000",  // 1 FTM
  network: "mainnet",
});

Server — Verify & Settle

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

const result = await verifyAndSettle({
  paymentHeader: req.headers["x-payment"],
  expectedRecipient: "0xdef456...",
  expectedAmountWei: "1000000000000000000",
  network: "mainnet",
});

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

Sonic Support

Pass network: "sonic" to use the Sonic (S) chain (chain ID 146):

const paymentHeader = await createPayment({
  senderPrivateKey: "0xabc123...",
  recipientAddress: "0xdef456...",
  amountWei: "1000000000000000000",
  network: "sonic",
});

Security

• Replay protection: In-memory Map with 1-hour TTL. Multi-instance deployments MUST use Redis/DB.
• Fail-closed: If balance query or RPC fails, the payment is REJECTED.
• On-chain verification: Signed transaction fields (to, value, chainId) are parsed and verified before broadcast.

License

MIT — Erudite Intelligence LLC