mpp-skale

SKALE payment method for MPP (Metered Payment Protocol)

Enables private, gasless payments on SKALE Network using confidential tokens with BITE encryption and EIP-3009 gasless transfers.

Features

• 4 Payment Modes:

  • Normal: Standard ERC-20 transfer
  • Gasless: EIP-3009 authorization (off-chain signing)
  • Confidential: BITE encrypted transfer (amount hidden)
  • Confidential Gasless: BITE + EIP-3009 (maximum privacy + convenience)

• Multi-Token Support: Accept multiple tokens in a single payment endpoint

• Replay Protection: Built-in authorization nonce tracking

• SKALE BITE Sandbox: Ready for testnet (Chain ID: 103698795)

Installation

npm install mpp-skale
# or
pnpm add mpp-skale
# or
yarn add mpp-skale

Quick Start

Client (Browser/Agent)

import { Mppx } from 'mppx/client'
import { skale as clientSkale } from 'mpp-skale'
import { privateKeyToAccount } from 'viem/accounts'

const account = privateKeyToAccount('0x...')

const mppx = Mppx.create({
  methods: [
    clientSkale({
      account,
      confidential: true,  // Enable BITE encryption
      gasless: false,      // Client submits tx
    }),
  ],
})

// Automatically handles 402 challenges
const response = await mppx.fetch('https://api.example.com/paid-resource')
console.log(response.status) // 200

Server (API)

import { Mppx } from 'mppx/server'
import { skale as serverSkale } from 'mpp-skale'
import { createPublicClient, http } from 'viem'

const client = createPublicClient({
  chain: {
    id: 103698795,
    name: 'SKALE BITE Sandbox',
    nativeCurrency: { decimals: 18, name: 'sFUEL', symbol: 'sFUEL' },
    rpcUrls: { default: { http: ['https://base-sepolia-testnet.skalenodes.com/v1/bite-v2-sandbox'] } },
  },
  transport: http(),
})

const mppx = Mppx.create({
  methods: [
    serverSkale({
      getClient: () => client,
      confidential: true,
      gasless: false,
      tokens: [
        { address: '0x36A9040...', symbol: 'STUB', decimals: 18 },
      ],
      recipient: '0xYourServerAddress',
      testnet: true,
    }),
  ],
  realm: 'api.example.com',
  secretKey: 'your-secret',
})

// Express-style handler
export async function handler(req, res) {
  const result = await Mppx.toNodeListener(
    mppx.charge({ amount: '0.1', decimals: 18 })
  )(req, res)
  
  if (result.status === 200) {
    console.log('Payment received:', result.receipt)
    res.end('Premium content')
  }
}

Configuration

Client Options

clientSkale({
  account: Account,           // Required: Viem account
  getClient?: () => Client, // Optional: Custom viem client
  confidential?: boolean,   // Default: false
  gasless?: boolean,        // Default: false
  validDuration?: number,    // Default: 300 (5 minutes)
})

Server Options

serverSkale({
  getClient: () => Client,  // Required: Viem client factory
  confidential?: boolean,   // Default: false
  gasless?: boolean,        // Default: false
  currency?: string,        // Single token address
  tokens?: TokenOption[],   // Multiple tokens (overrides currency)
  recipient?: string,       // Payment recipient address
  testnet?: boolean,       // Default: true
  store?: AuthorizationStore, // Replay protection store
  useMulticall?: boolean,   // Default: false
  waitForConfirmation?: boolean, // Default: true
})

Examples

See the examples/ directory for complete working examples:

• normal.ts - Standard ERC-20 transfer
• gasless.ts - EIP-3009 authorization
• confidential.ts - BITE encrypted transfer
• confidential-gasless.ts - BITE + EIP-3009

Network Details

SKALE BITE Sandbox (Testnet)

• Chain ID: 103698795
• RPC: https://base-sepolia-testnet.skalenodes.com/v1/bite-v2-sandbox
• BITE Address: 0x42495445204D452049274d20454e435259505444
• STUB Token: 0x36A9040DAC18D008a11Dc600d5EB1Cc89bb45200

License

MIT