M2M Payments Sample App

All the APIs you need for machine-to-machine payments.

An open source sample app that showcases how you can enable your agents to:

  • Top up credits by card, with no KYC
  • Hold a non-custodial wallet they can spend from
  • Pay any x402 or MPP endpoint

Build your own agent payments stack. Your users, your brand.

Try it liveView on GitHub

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How it works

Three APIs, one wallet, one approval screen you host.

  1. Credits only pay for machine services, so they are a closed-loop token. Crossmint runs the card checkout under the same merchant category as buying OpenAI or Anthropic credits, with Visa and Mastercard, and no identity document is asked for.

    • One credit is one dollar.
    • Visa, Mastercard, Apple Pay and Google Pay.
    • Funds land in the user's own wallet.

  2. The wallet is non-custodial: a device signer in the browser, an email signer as backup. Your agent gets a server signer the user approves once.

    • Revocable any time from the app.
    • The agent never holds a key.
    • Powered by Crossmint smart wallets.

  3. The server handles the 402 handshake, signs with the agent's signer and retries with the payment. You get the response and the receipt.

    • x402 and the Machine Payments Protocol (MPP).
    • A cap per call, checked before anything is signed.
    • Transfers and raw transactions too.

Support any agentic user experience

The same APIs behind a chat app, a messaging bot, an MCP host or a terminal agent.

acme.com/app
Acme Agent
Put together a market brief on EV charging in Europe
On it. I need to pay a research API for the sources, so I need to use your wallet.
Wallet access requestResearch API calls · confirm by email code
Agent
Acme Agent
Can do
Pay x402 and MPP services
From
0x7a3F…9c2E
Message the agent

Approve inside your own app

Your chat, your components. Approve wallet access and top up credits inline.

Try it

Customize the full end to end experience. Your app, your components.

Crossmint gives you the APIs. You design your own flow and experience.

See examples

Try it live

Log in, top up credits, and let the agent pay a machine. Every experience runs on the same APIs. Staging runs on test credits.

Open the example app

Questions

Credits are a closed-loop token. They buy machine services from your agent, and nothing else.

  • Machine services only: inference, search, data. Credits do not cash out.
  • Buying closed-loop value for digital services falls under the same merchant category as buying OpenAI or Anthropic credits, and Visa and Mastercard treat it that way.
  • Crossmint runs the card checkout under that category, so the user is never asked for an identity document.

No. The wallet is the user's, with a device signer made in the browser and an email signer as recovery.

  • The device signer's key never leaves the browser.
  • The agent gets a server signer the user approves once, with an email code, and can revoke from the app at any time.
  • The agent never holds a key, a card or a Crossmint credential.

x402 and the Machine Payments Protocol (MPP), both over HTTP. It can also send plain transfers and raw transactions on Base.

It is a sample app. It shows the flows end to end, and staging uses test credits on Base Sepolia. Review it before shipping it to your users.