MPP vs x402
Which machine payment flow fits your resource and payment methods?
Both address machine-oriented payments. MPP’s team documents x402 exact-flow support in its SDK; that is a concrete interoperability claim with a specific scope, not proof every method is interchangeable. Compare supported methods, request semantics, facilitator or settlement dependencies, refunds and operational ownership for your exact use case. Public SDK availability is not a production test.
What this establishes
A practical way to inspect evidence and make the next merchant decision.
What it cannot establish
Live merchant deployment, private account eligibility, purchase completion or guaranteed AI selection.
The overlap
Both address machine-oriented payments. MPP’s team documents x402 exact-flow support in its SDK; that is a concrete interoperability claim with a specific scope, not proof every method is interchangeable.
The merchant decision
Compare supported methods, request semantics, facilitator or settlement dependencies, refunds and operational ownership for your exact use case. Public SDK availability is not a production test.
Where they overlap.
Where they complement.
Compare roles and implementation work. A shared capability does not make two systems interchangeable.
| Decision dimension | MPP | x402 |
|---|---|---|
| Layer | Payments | Payments |
| Role | Lets agents negotiate and pay for service access across supported payment methods. | Connects a resource request to payment requirements and a paid retry. |
| Status | active individual Internet-Draft | published specification |
| Version | draft-httpauth-payment-01 · normative core; broader SDK/method versions separate | 2 |
| Discovery | Payment offers for services | Resource-specific payment requirements |
| Checkout | Not a retail checkout model | Outside retail checkout scope |
| Payment | Core role: service access | HTTP 402 payment flow |
| Authorization | Payment method and intent dependent | Scheme-dependent |
| Transport | HTTP-oriented; SDK integration | HTTP-native |
| Adoption | Team documents service integrations; not independently transacted | Public implementations; merchant deployment Unknown |
| What it does not solve | Does not supply retail catalogs, fulfillment or a complete store checkout. | Does not describe a retail order, shipping policy or return workflow. |
| Evidence | 3 source record(s) Checked 2026-09-28 draft; scope-dependent | 3 source record(s) Checked 2026-09-28 live; scope-dependent |
Unknown ≠ unsupported. Announcements and product documentation are not proof of your live integration.
Overlap and replacement risk
These entries occupy a related layer. Test their exact operations, data paths and eligibility before treating one as a substitute. Keep your source of product truth, fulfillment responsibility and payment obligations explicit.
Go to the source.
Primary documentation records what is publicly stated. It does not independently prove outcomes or your account’s eligibility.
Claim scope: Agent payments for web services
Open payment-method-extensible protocol; no retail-wide adoption inferred.
Claim scope: SDK interoperability
MPP team documents x402 exact flows in mppx.
Claim scope: Version metadata and documented changes only; not merchant adoption.
SHA-256 of retrieved source response: fcb287fd83f5a74d9ebf5b06ade3849cbad9ca4581a88fc075554afc28956b69
Claim scope: HTTP payment flow
Repository says canonical development moved to x402 Foundation; Coinbase repo is a development fork.
Claim scope: Internet-native payments
Claim scope: Version metadata and documented changes only; not merchant adoption.
SHA-256 of retrieved source response: aa6dc5e8ccc7758689945fc7502674f51cd0f21f09ec886aa1dbc4cd86bc81b6