@0xsquid/mpp

squid-mpp

Cross-chain payment method for mppx that fulfills MPP charge challenges via Squid Router.

Given a viem Account, it scans all Squid-supported EVM chains for available balances, selects a viable source token, bridges it to the challenge currency on Tempo mainnet, and returns a credential containing the destination tx hash.

Agent on Base (or other chain)  →  Squid bridge  →  Tempo chain  →  MPP recipient

Install

npm install @0xsquid/mpp

Usage

import { Mppx } from "mppx/client"
import { squid } from "@0xsquid/mpp"
import { privateKeyToAccount } from "viem/accounts"

const account = privateKeyToAccount(process.env.PRIVATE_KEY! as `0x${string}`)

const { fetch: mppxFetch } = Mppx.create({
  polyfill: false,
  methods: [
    squid({
      account,
      integratorId: "my-app"
    })
  ]
})

const response = await mppxFetch("https://some-mpp-api.com/resource")
console.log(await response.json())

Options

How it works

1. Receives a Tempo charge challenge { amount, currency, recipient } from a 402 response
2. Queries Squid for all supported tokens across EVM chains and finds ones held by the account
3. Selects the best source token and constructs a bridge route to the challenge currency on Tempo
4. Executes the bridge transaction and polls for the destination tx on Tempo (every 5s, up to 5min)
5. Returns a credential { type: "hash", hash } containing the Tempo destination tx hash

The server verifies the credential by fetching the receipt from Tempo and checking that the Transfer event matches the challenge parameters exactly (token address, recipient, amount).