Protocol

MPP Compatibility

What the Machine Payments Protocol shares with Opus Protocol, where the two part ways, and what that means for agents and services.

Stripe and Tempo released the Machine Payments Protocol (MPP) in March 2026. It is an open standard for payments between machines over HTTP, and it is tracked at the IETF. The pattern underneath is the x402 one (request, pay, retry), with Stripe’s billing stack and Tempo’s L1 added as the settlement layer.

Opus Protocol is built so that MPP clients can read it. An agent that speaks MPP can pay Opus Protocol endpoints; the difference is that settlement happens on Robinhood Chain instead of on Stripe or Tempo rails.

MPP and x402 side by side

Both protocols follow one shape: a 402 Payment Required response states the price, the client settles it, and the retried request carries proof. Where MPP adds value is precision. Its IETF draft pins down:

  • A common schema for negotiating payment
  • Named settlement profiles (currently Stripe and Tempo, with space for others)
  • Structured error codes and defined retry behavior

A payment response from an Opus Protocol endpoint should parse cleanly in any MPP-compliant agent. The only point of divergence is settlement: MPP specifies Stripe and Tempo profiles, and Opus Protocol settles on Robinhood Chain.

For agent developers

If your agent already implements the MPP client specification (perhaps via a framework), it can call Opus Protocol-powered endpoints as is. No code changes are needed. The agent reads the 402, picks a scheme it recognizes, pays, and retries. At that layer, the chain doing the settling is not visible.

One field will look different to an MPP agent: network in the payment object.

{
  "network": "robinhood-mainnet",
  "token": "0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168"
}

Were the endpoint settling through Stripe, that slot would hold Stripe’s settlement details instead. Any agent that has a Robinhood Chain wallet and can reach the Opus Protocol Facilitator is able to pay.

For service providers

Services already taking MPP payments through Stripe can add Opus Protocol as a second settlement option without changing their API structure. The payment gate appends a Robinhood Chain native entry to the 402 response next to the Stripe entry, and each agent selects whichever one its wallet can use.

IETF roadmap

Our plan is to submit an MPP settlement profile native to Robinhood Chain to the IETF draft, sitting alongside the Stripe/Tempo submission. This is scheduled for Phase 3 (Q1 2027), by which point the MPP specification should be mature enough to take on an alternative settlement profile.

Status today

For the duration of the beta, MPP compatibility is informal. The SDK produces and accepts responses whose structure lines up with MPP. Formal certification against the IETF draft will come after the beta ends. Agent framework authors who want to check Opus Protocol’s MPP compatibility against their own stack can get in touch through the beta program.