@abstract-foundation/mpp

MPP payment method plugin for the Abstract blockchain. Enables paid API access via two settlement mechanisms: one-time ERC-3009 charges and ERC-20 payment channel sessions.

Install

npm install @abstract-foundation/mpp mppx viem zod

How it works

Both payment methods follow the same HTTP protocol:

1. Client requests a resource
2. Server responds 402 Payment Required with WWW-Authenticate: Payment method="abstract"
3. Client signs and retries with Authorization: Payment <credential>
4. Server verifies, settles on-chain, responds 200 OK with Payment-Receipt

The mppx framework handles the 402 negotiation loop. This package implements the Abstract-specific signing and settlement logic on top.

Payment methods

Charge (ERC-3009)

One-time payments. The client signs ERC-3009 TransferWithAuthorization typed data — no transaction from the client side. The server broadcasts transferWithAuthorization() on USDC.e, paying gas (optionally via an Abstract paymaster).

Session (Payment channels)

Streaming payments via AbstractStreamChannel.sol. The client opens a channel once (approve + open()), depositing USDC.e into escrow. Each subsequent request exchanges a signed EIP-712 voucher with a cumulative amount. The server accumulates the highest voucher and calls settle() or close() to finalize.

Usage

Server

import { Mppx } from 'mppx/server'
import { abstract } from '@abstract-foundation/mpp/server'
import { privateKeyToAccount } from 'viem/accounts'

const mppx = Mppx.create({
  methods: [
    abstract.charge({
      account: privateKeyToAccount(process.env.SERVER_PRIVATE_KEY),
      recipient: '0xYourRecipientAddress',
      amount: '0.01',
      testnet: true,
    }),
    abstract.session({
      account: privateKeyToAccount(process.env.SERVER_PRIVATE_KEY),
      recipient: '0xYourRecipientAddress',
      amount: '0.001',
      suggestedDeposit: '1',
      testnet: true,
    }),
  ],
  secretKey: process.env.MPP_SECRET_KEY,
})

Client

import { abstractCharge, abstractSession } from '@abstract-foundation/mpp/client'
import { privateKeyToAccount } from 'viem/accounts'

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

const charge = abstractCharge({ account })
const session = abstractSession({ account, deposit: '10' })

Both return mppx method objects that plug directly into the mppx client.

Exports

| Entry point | Description | |---|---| | @abstract-foundation/mpp | All exports (client + server + constants) | | @abstract-foundation/mpp/client | Client-side charge and session methods | | @abstract-foundation/mpp/server | Server-side charge and session handlers |

Chain support

| | Testnet (11124) | Mainnet (2741) | |---|---|---| | USDC.e | 0xbd28...008C61 | 0x84A7...987e1 | | AbstractStreamChannel | 0x2963...0923c | 0x2963...0923c |

The plugin defaults to mainnet. Pass testnet: true on the server or let the server challenge dictate the chain on the client.

Paymaster support

Abstract uses ZKsync-native paymasters. Pass paymasterAddress to sponsor gas:

abstract.charge({
  account,
  recipient: '0x...',
  amount: '0.01',
  paymasterAddress: '0xYourPaymasterContract',
})

Smart wallet support

Client-side signing supports both EOA and ERC-1271 smart wallets via viem's typed data signing.

License

MIT