# MPP

> Stripe and Tempo's open standard for billing AI agents over HTTP — agents discover prices, pay, subscribe and reconcile across stablecoins, cards and BNPL, with cryptographic receipts.

_The Agent Protocol Atlas · /protocols/mpp · [JSON](/api/protocols/mpp) · [all The Agent Protocol Atlas](/protocols)_

- **name:** MPP
- **full_name:** Machine Payments Protocol
- **layer:** payments
- **creator:** Stripe + Tempo
- **status:** live (shipped 2026; IETF Internet-Draft)
- **year:** 2026
- **one_liner:** Stripe and Tempo's open standard for billing AI agents over HTTP — agents discover prices, pay, subscribe and reconcile across stablecoins, cards and BNPL, with cryptographic receipts.
- **spec_url:** https://stripe.com/blog/machine-payments-protocol
- **snippet:**

```
HTTP 402 + machine-readable price discovery → pay (stablecoin/card) → cryptographic receipt, in one cycle.
```
- **abbreviation:** MPP
- **also_known_as:** Machine Payments Protocol, Stripe/Tempo MPP
- **canonical_spec_url:** https://stripe.com/blog/machine-payments-protocol
- **entity_uri:** https://stripe.com/blog/machine-payments-protocol
- **taxonomy_layer:** payments
- **sub_layer:** machine-billing-over-http
- **protocol_type:** settlement
- **central_problem:** Gives AI agents a standard way to discover prices, pay for resources, manage subscriptions, and reconcile balances over HTTP across stablecoins, cards, and BNPL — with cryptographic receipts.
- **maintainer:** Stripe + Tempo (co-authored); proposed to the IETF as a Standards Track Internet-Draft
- **governance_body:** vendor (Stripe + Tempo); IETF Internet-Draft submitted
- **license:** — (verify-against-primary-at-build)
- **maturity_tag:** emerging
- **current_spec_version:** — (verify-against-primary-at-build)
- **spec_date:** 2026-03-18
- **launch_date:** 2026-03-18
- **last_verified:** 2026-06-15
- **transport:** HTTP (formalizes the 402 status code); settlement via Stripe PaymentIntents with Tempo as default stablecoin chain
- **core_mechanism:** MPP gives HTTP's 402 status code a formal specification so agents can, in one request-response cycle, discover pricing, pay for a resource (stablecoins via Tempo, cards via Stripe/Visa, Bitcoin via Lightning, or custom methods), and receive a cryptographic receipt. It is lifecycle-aware — subscriptions, streaming charges, cancellations, and balance reconciliation are first-class — with funds settling through Stripe PaymentIntents.
- **discovery_endpoint:** HTTP 402 price-discovery response (per-resource); MPP Services Directory
- **settlement_type:** stablecoin (Tempo) / card-rail (Stripe, Visa) / Bitcoin (Lightning) / custom
- **adoption_metric:** 100+ services listed in the MPP Services Directory (per the Stripe/Tempo announcement) (source: https://stripe.com/blog/machine-payments-protocol)
- **notable_adopters:** {"value":"Stripe (co-author; PaymentIntents settlement)","source":"https://stripe.com/blog/machine-payments-protocol"}, {"value":"Tempo (co-author; default stablecoin chain)","source":"https://stripe.com/blog/machine-payments-protocol"}
- **relationships:** {"predicate":"competes_with","target":"x402","note":"MPP and x402 both formalize HTTP 402 for agent payments; MPP adds lifecycle primitives (subscriptions, reconciliation) and multi-rail settlement."}, {"predicate":"complements","target":"ap2","note":"Both target agent payments; MPP is an HTTP 402 billing protocol with Tempo settlement, AP2 is a mandate framework across rails."}
- **ideal_use_case:** Billing AI agents for API/resource access over HTTP with subscriptions, streaming charges, and multi-rail settlement.
- **when_to_use:** When you need lifecycle-aware agent billing (not just one-shot payments) across stablecoins, cards, and BNPL with cryptographic receipts.
- **when_not_to_use:** When a simple inline stablecoin micropayment (x402) or a mandate-routed checkout (AP2) is all you need.
- **code_example:** HTTP/1.1 402 Payment Required
MPP-Accepts: stablecoin; chain=tempo; price=0.02 USD

# Agent pays and retries; server returns a cryptographic receipt:
MPP-Receipt: <signed receipt>
- **source:** Stripe + Tempo Machine Payments Protocol (shipped 2026-03-18; formalizes HTTP 402; price discovery + subscriptions + reconciliation; stablecoin via Tempo, cards via Stripe/Visa, Bitcoin via Lightning; Stripe PaymentIntents settlement; IETF Internet-Draft; 100+ services directory): https://stripe.com/blog/machine-payments-protocol . Listed for addition in research §2.
- **agent_readiness_link:** agent-readiness/x402
- **layer_legacy:** payment