MPP
Pay-per-use AgentMail with Stripe’s Machine Payments Protocol
Pay-per-use AgentMail with Stripe’s Machine Payments Protocol
MPP (Machine Payments Protocol) is Stripe’s open protocol that enables machine-to-machine payments. By integrating MPP with AgentMail, your agents can pay for API usage directly without managing API keys or subscriptions.
To authenticate with MPP instead of an API key, you must use the MPP-specific base URLs below. These replace the default AgentMail base URLs and route requests through the MPP payment layer.
When you pass an mppx client to AgentMailClient, the SDK automatically handles payment negotiation for each API request. The MPP client signs payments using your wallet, enabling your agent to pay per request seamlessly.
This means your agent can use the full AgentMail API (inboxes, messages, threads, attachments) without needing a traditional API key. Payment happens per-request via Stripe’s Machine Payments Protocol.