Solobank
Machine Payments Protocol

Accept USDC
on Solana.

Your AI agent pays automatically. No API keys. No credit cards. Just USDC.

$pnpm add @solobank/mpp-solana mppx @solana/web3.js
~400ms
Solana settlement
<$0.001
Per transaction
MIT
Open standard

For API developers

Accept USDC payments on any HTTP endpoint. Five lines of code.

server.ts
import { Mppx } from 'mppx';
import { solanaServer } from '@solobank/mpp-solana';

const mppx = Mppx.create({
  methods: [
    solanaServer({
      recipient: 'YOUR_SOLANA_WALLET',
    }),
  ],
});

Sub-second settlement

~400ms finality on Solana. Payments confirm before the response is sent.

Direct to wallet

USDC goes straight to your Solana address. No intermediary, no custodian.

Minimal gas

<$0.001 per transaction. Cheaper than a credit card swipe fee.

For AI agents

No API keys. No credit cards. Just money.

Autonomous payments

Agents pay APIs without human intervention. Just a wallet and USDC.

On-chain verification

Every payment is cryptographically provable via Solana transaction signatures.

Multi-account support

Aggregate balances across multiple SPL token accounts automatically.

client.ts
import { Connection, Keypair } from '@solana/web3.js';
import { Mppx } from 'mppx/client';
import { solanaClient } from '@solobank/mpp-solana';

const connection = new Connection(rpcUrl);
const signer = Keypair.generate();

const mppx = Mppx.create({
  methods: [
    solanaClient({
      connection,
      signer: { publicKey, signTransaction },
    }),
  ],
});

How MPP works

The HTTP 402 Payment Required flow

1

Request

Agent calls a paid API endpoint.

2

402 Response

Server responds with 402 Payment Required + payment challenge.

3

Pay on Solana

Agent signs a USDC transfer on Solana (~400ms finality).

4

Retry with proof

Agent retries the request with the Solana signature as credential.

Why Solana

The fastest, cheapest settlement layer for machine payments.

~400ms
Transaction finality

Payments confirm in under a second. No waiting, no polling.

<$0.001
Average gas cost

Thousands of payments for pennies. Cheaper than any card network.

Native USDC
Circle-issued

Not bridged, not wrapped. Official Circle USDC on Solana mainnet.

Open standard

MPP is a non-proprietary protocol. Any client can pay any server. No vendor lock-in.

Start accepting USDC payments

Add Solana payments to your API in minutes.

pnpm add @solobank/mpp-solana mppx @solana/web3.js