Protocol

MPP Compatibility

Recur's relationship to the Machine Payments Protocol from Stripe and Tempo.

MPP (Machine Payments Protocol) is an open, IETF-tracked standard for machine-to-machine payments over HTTP. It was published in March 2026 by Stripe and Tempo, extending the x402-style request-pay-retry pattern with Stripe’s billing infrastructure and Tempo’s L1 settlement layer.

Recur is designed to be compatible with MPP-speaking clients, routing their payments through Solana rather than Stripe/Tempo infrastructure.

How MPP relates to x402

MPP and x402 share the same core mechanic: a 402 Payment Required response signals that a resource requires payment, the client pays, and the client retries with a proof. MPP formalizes this into an IETF draft with:

  • A standardized payment negotiation schema
  • Defined settlement profiles (Stripe, Tempo, and potentially others)
  • Structured error codes and retry semantics

Recur’s HTTP payment response is designed to be parseable by any MPP-compliant agent. The differences are at the settlement layer: where MPP routes to Stripe/Tempo, Recur routes to Solana.

What this means for agent developers

An agent built to speak MPP — for example, an agent using a framework that integrates the MPP client spec — can interact with Recur-powered endpoints without code changes. The agent reads the 402 response, finds a payment scheme it understands, executes the payment, and retries. From the agent’s perspective, the settlement layer is opaque.

The only difference an MPP agent would notice is the network field in the payment object:

{
  "network": "solana-mainnet",
  "token": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v"
}

Versus a Stripe-backed MPP endpoint which would specify Stripe’s settlement details. If the agent has a Solana wallet and access to the Recur Facilitator, it can pay.

What this means for service providers

If your service already accepts MPP payments via Stripe, you can add Recur as a second settlement option without changing your API structure. The Recur payment gate adds a Solana-native option to your 402 response alongside your existing Stripe option. Agents pick the one that matches their wallet.

Recur’s IETF roadmap

Recur intends to submit a Solana-native MPP settlement profile to the IETF draft alongside the Stripe/Tempo submission. This is planned for Phase 3 (Q1 2027) once the MPP specification has stabilized sufficiently for an alternative settlement profile submission.

Current status

During beta, Recur tracks MPP compatibility informally. The SDK is designed to produce and consume responses that are structurally compatible with MPP, but formal certification against the IETF draft is post-beta work. If you are building an agent framework and want to validate Recur’s MPP compatibility in your stack, reach out through the beta program.