@suimpp/mpp

Sui USDC payment method for the Machine Payments Protocol (MPP). Accept and make payments on any API — the first MPP implementation on Sui.

Website · GitHub · SDK · CLI

Migrated from @mppsui/mpp. If you were using the old package, switch your imports to @suimpp/mpp.

What is MPP?

The Machine Payments Protocol is an open standard by Stripe and Tempo Labs for agent-to-service payments. When a server returns HTTP 402 Payment Required, the client pays automatically and retries — no API keys, no subscriptions, no human approval.

@suimpp/mpp adds Sui USDC as a payment method. It works with any MPP-compatible client or server via the mppx SDK.

Installation

npm install @suimpp/mpp mppx

Accept Payments (Server)

Add payments to any API in 5 lines:

import { sui } from '@suimpp/mpp/server';
import { Mppx } from 'mppx';

const SUI_USDC = '0xdba34672e30cb065b1f93e3ab55318768fd6fef66c15942c9f7cb846e2f900e7::usdc::USDC';

const mppx = Mppx.create({
  methods: [sui({ currency: SUI_USDC, recipient: '0xYOUR_ADDRESS' })],
});

export const GET = mppx.charge({ amount: '0.01' })(
  () => Response.json({ data: 'paid content' })
);

No webhooks. No Stripe dashboard. No KYC. USDC arrives directly in your wallet.

Make Payments (Client)

import { sui } from '@suimpp/mpp/client';
import { Mppx } from 'mppx/client';
import { SuiGrpcClient } from '@mysten/sui/grpc';
import { Ed25519Keypair } from '@mysten/sui/keypairs/ed25519';

const client = new SuiGrpcClient({
  baseUrl: 'https://fullnode.mainnet.sui.io:443',
  network: 'mainnet',
});
const signer = Ed25519Keypair.deriveKeypair('your mnemonic');

const mppx = Mppx.create({
  methods: [sui({ client, signer })],
});

const response = await mppx.fetch('https://api.example.com/resource');
// If the API returns 402, mppx pays automatically via Sui USDC.

With t2000 SDK

If you're using the t2000 SDK, payments are even simpler:

import { T2000 } from '@t2000/sdk';

const agent = await T2000.create({ pin: 'my-secret' });

const result = await agent.pay({
  url: 'https://api.example.com/generate',
  body: { prompt: 'a sunset' },
  maxPrice: 0.05,
});
// Handles 402 → pay → retry automatically.
// Safeguards enforced (max per tx, daily limits).

CLI

t2000 pay https://api.example.com/data --max-price 0.10

t2000 pay https://api.example.com/analyze \
  --method POST \
  --data '{"text":"hello"}' \
  --max-price 0.05

How It Works

Agent                    API Server
  │                          │
  │── GET /resource ────────>│
  │<── 402 Payment Required ─│
  │    {amount, currency,    │
  │     recipient}           │
  │                          │
  │── USDC transfer on Sui ──│  (~400ms finality)
  │                          │
  │── GET /resource ────────>│
  │   + payment credential   │── verify TX on-chain via gRPC
  │   (Sui tx digest)        │
  │<── 200 OK + data ────────│

No facilitator. No intermediary. The server verifies the Sui transaction directly via gRPC.

Server API

sui(options)

Creates a Sui payment method for the server.

import { sui } from '@suimpp/mpp/server';

const method = sui({
  currency: SUI_USDC,         // Sui coin type (e.g. USDC)
  recipient: '0xYOUR_ADDR',   // Where payments are sent
  decimals: 6,                // Optional: currency decimals (default: 6)
  rpcUrl: '...',              // Optional: custom gRPC endpoint
  network: 'mainnet',         // Optional: 'mainnet' | 'testnet' | 'devnet'
  registryUrl: 'https://suimpp.dev/api/report', // Optional: report payments to suimpp.dev
});

Verification checks:

• Transaction succeeded on-chain
• Payment sent to correct recipient (address-normalized comparison)
• Amount >= requested (BigInt precision, no floating-point)

Client API

sui(options)

Creates a Sui payment method for the client.

import { sui } from '@suimpp/mpp/client';

const method = sui({
  client: grpcClient,            // Any Sui client (SuiGrpcClient, etc.)
  signer: ed25519Keypair,        // Signer from @mysten/sui/cryptography
  decimals: 6,                   // Optional: currency decimals (default: 6)
  execute: async (tx) => {       // Optional: custom execution (gas sponsor, etc.)
    return myGasManager.execute(tx);
  },
});

| Option | Type | Required | Description | |--------|------|----------|-------------| | client | ClientWithCoreApi | Yes | Any Sui client implementing the core API | | signer | Signer | Yes | Any Signer from @mysten/sui/cryptography — Ed25519Keypair works | | decimals | number | No | Decimal places for the currency (default: 6) | | execute | (tx: Transaction) => Promise<{ digest: string }> | No | Override transaction execution (e.g. gas sponsor/manager) |

The client uses the coinWithBalance intent to automatically resolve, merge, and split coins for the exact payment amount, then signs and broadcasts the transaction (or delegates to execute if provided).

Constants

SUI_USDC_TYPE

The Sui coin type for Circle-issued USDC on mainnet.

import { SUI_USDC_TYPE } from '@suimpp/mpp';
// '0xdba34672e30cb065b1f93e3ab55318768fd6fef66c15942c9f7cb846e2f900e7::usdc::USDC'

Utilities

parseAmountToRaw(amount, decimals)

Converts a string amount to BigInt raw units without floating-point math.

parseAmountToRaw('0.01', 6);  // 10000n
parseAmountToRaw('1.50', 6);  // 1500000n

Why Sui?

MPP is chain-agnostic. We chose Sui because agent payments need:

| | Sui | |---|---| | Finality | ~400ms | | Gas | <$0.001 per payment | | USDC | Circle-issued, native | | Verification | Direct gRPC — no facilitator |

Testing

pnpm --filter @suimpp/mpp test    # 13 tests
pnpm --filter @suimpp/mpp typecheck

License

MIT — see LICENSE