# 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 (Tempo and Solana), settling through Stripe's existing infrastructure. The spec is open at mpp.dev. Generally available per the Stripe changelog: SPTs available in all US states and internationally; stablecoin payments in 30+ countries. October 2026 added session-based streaming payments and dynamic pricing (public preview).

## At a glance

| Field | Value |
| --- | --- |
| Name | MPP |
| Layer | payment-execution |
| Category | hybrid |
| Status | live |
| Created by | Stripe, Tempo |
| Launched | 2026-03 |
| Rails | cards, stablecoins, USDC, Solana |
| Settlement | Settles through Stripe (PaymentIntents), across card and stablecoin rails; stablecoin settlement via the Tempo blockchain and Solana. |
| Reversible | yes |
| Human in loop | optional |
| D2C fit | moderate |
| B2B fit | strong |
| Spec | https://mpp.dev |
| Last verified | 2026-10-26 |

## 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 and **Solana** (USDC). Stripe's machine-payments surface also supports **x402** for stablecoin-only flows on Base.
- **Payment shapes.** Covers **one-shot, recurring, and streaming** payments, so an agent can pay once or maintain ongoing/metered obligations. **Session-based payments** (October 2026, public preview) let agents pre-authorize a maximum and pay per unit of work (tokens, seconds, rows) in sub-cent increments with periodic settlement.
- **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**. MPP is **generally available** per the Stripe changelog: SPTs are available in all US states and internationally, stablecoin payments in 30+ countries. Dynamic pricing and session-based streaming payments shipped in October 2026 as public previews.

## 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.
- Session-based and dynamic pricing features are still in public preview; integrations should track Stripe's changelog for interface changes.

## 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)
5. [Stripe Changelog — Accept payments on x402 and MPP (General availability)](https://stripe.com/shipped) — Stripe

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_Source: payful.ai — independent editorial reference. Verified 2026-10-26._