Do not collapse every payment acronym into one job
A payment method, a payment processor, an authorization protocol and a commerce protocol can all participate in one purchase. AP2 describes authorization evidence within a commerce flow. MPP and x402 focus on machine-oriented payment interactions. These roles can overlap at integration boundaries without being interchangeable retail checkout systems.
Ask scoped questions of a provider
Which payment methods and regions are supported for your merchant entity? Who validates authority? What evidence survives a retry or dispute? A partner logo or standards endorsement is insufficient to answer those questions. Treat provider statements as documentation of a product’s claimed scope until you have evidence for your configuration.
Keep this guide outside transaction execution
The platform offers architecture and evidence comparisons. It does not handle payment credentials, create transactions or provide merchant-specific legal eligibility advice. Any future paid product requires a separately approved payment and payout route.