# Machine Payments Protocol (MPP)

> An open, internet-native protocol for machine and agent payments, co-authored by Stripe and Tempo. Spans both card (via Shared Payment Tokens) and stablecoin rails, settling through Stripe's existing infrastructure. The spec is open at mpp.dev; Stripe acceptance is in early access as of September 2026.

## At a glance

| Field | Value |
| --- | --- |
| Name | MPP |
| Layer | payment-execution |
| Category | hybrid |
| Status | beta |
| Created by | Stripe, Tempo |
| Launched | 2026-03 |
| Rails | cards, stablecoins, USDC |
| Settlement | Settles through Stripe (PaymentIntents), across card and stablecoin rails; stablecoin settlement via the Tempo blockchain. |
| Reversible | yes |
| Human in loop | optional |
| D2C fit | moderate |
| B2B fit | strong |
| Spec | https://mpp.dev |
| Last verified | 2026-09-03 |

## How it works

MPP is an **open standard** co-authored by Stripe and Tempo that lets **agents pay for APIs and services programmatically** without a checkout UI.

- **402 challenge flow.** When an agent requests a resource, the service returns an HTTP `402` response with payment details. The agent authorizes the payment, retries the request, and receives the resource with a receipt.
- **Rail coverage.** MPP spans **card and stablecoin rails**. Cards are handled via **Shared Payment Tokens (SPTs)** — scoped grants that let an agent use a customer's payment method with usage and expiration limits. Stablecoin payments settle via the **Tempo** blockchain. Stripe's machine-payments surface also supports **x402** for stablecoin-only flows.
- **Payment shapes.** Covers **one-shot, recurring, and streaming** payments, so an agent can pay once or maintain ongoing/metered obligations.
- **Settlement.** Flows settle through **Stripe PaymentIntents**, which means agent payments reuse Stripe's reconciliation, reporting, and (for card rails) dispute handling.

The specification is open at **mpp.dev**. Stripe acceptance remains in **early access**; dynamic pricing for MPP is on Stripe's public preview roadmap. This entry is marked **beta** accordingly.

## Tradeoffs

- Reversibility is mixed: card-rail payments retain dispute/refund rights, but stablecoin settlement does not — a single 'reversible' flag over-simplifies, so confirm per rail.
- Settling through Stripe implies operating within Stripe's account, availability, and compliance model rather than a permissionless one.
- As an early-access surface, capabilities and interfaces may shift; integrations should track Stripe's changelog.

## Security & limitations

- Agent-initiated recurring/streaming payments require robust scoping and revocation to prevent runaway or manipulated charges.
- Where MPP bridges to stablecoin/x402 flows, the non-reversibility and custody considerations of on-chain settlement apply to that leg.
- Shared Payment Tokens carry scoped card access; token leakage or insufficient scope constraints could enable unauthorized charges.

## Fits together with

- x402

## Sources

1. [Machine payments — Overview](https://docs.stripe.com/payments/machine) — Stripe
2. [MPP payments — Machine Payments Protocol](https://docs.stripe.com/payments/machine/mpp) — Stripe
3. [Introducing the Machine Payments Protocol](https://stripe.com/blog/machine-payments-protocol) — Stripe, 2026-03
4. [MPP specification](https://mpp.dev) — MPP (Stripe & Tempo)

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_Source: payful.ai — independent editorial reference. Verified 2026-09-03._