COMPARISON
API Economy
API Economy
x402 vs MPP
Stablecoin HTTP payments vs Stripe + Tempo card-rail machine payments.
These two protocols both answer "how does a machine pay another machine," but from opposite ends of the financial system. x402 is HTTP-native, stablecoin-settled, and indifferent to merchant compatibility. MPP rides Visa and Mastercard rails with Stripe + Tempo clearing, optimised for merchants who already accept cards. They are complementary in production agents.
x402
vs
MPP
Side-by-side
The dimensions that actually matter.
| Dimension | x402 | MPP |
|---|---|---|
| Settlement | Stablecoins (USDC) on EVM chains | Card networks via Tempo clearing |
| Latency | <200 ms on Base mainnet | Card-network timelines (T+0 to T+2) |
| Merchant ubiquity | Anywhere with an x402 facilitator | Anywhere Stripe is accepted |
| Disputes / chargebacks | On-chain finality, no chargebacks | Card-network dispute primitives |
| Spec ownership | Coinbase + Cloudflare (open) | Stripe + Tempo |
| Best for | Per-call API payments, agent-to-agent settlement | Agentic checkout at card-accepting merchants |
Decision matrix
Which one, when.
x402
Pick x402 when…
- You are charging per API call or per task and want sub-second finality.
- Your buyer is another agent or service, not a consumer at a merchant.
- You want a zero-fee, programmable rail with no merchant onboarding.
MPP
Pick MPP when…
- You need to transact with merchants that already accept cards.
- Disputes, refunds, and chargebacks must work like a normal Stripe payment.
- Your finance team needs card-network reconciliation metadata.
both
Use both when…
- Your agent calls APIs (x402) and shops at consumer merchants (MPP).
- You want consistent governance across rails — same budgets, same audit trail.
- You are designing for the long-term: most agents will be multi-rail.
Bottom line
These are not substitutes. x402 wins programmable, micro-priced, agent-to-agent flows. MPP wins where merchants and the card network are already the source of truth. Production agents will live on both — and need one governance plane on top.
How xpay fits
xpay is the rail-agnostic control plane. The same Smart Proxy policies (budget, category, time, recipient, cumulative, per-tx) apply whether the call lands on an x402 facilitator or an MPP credential.