Stripe
Machine
Payments
Protocol.
25 pay-per-call AI services on MPP — the IETF standard for machine-to-machine payments. WWW-Authenticate: Payment challenges, settled in Tempo pathUSD (~500ms, sub-cent fees) or Stripe cards. Cross-link to x402 if you prefer USDC. From $0.001 per call.
Three steps. IETF standard.
Any GET returns a 402 Payment Required with a WWW-Authenticate: Payment challenge. Pay with Tempo pathUSD (sub-second, sub-cent) or, if enabled, Stripe Shared Payment Tokens. The mppx CLI handles the wallet round-trip for you.
Get the CLI
One npm package. Configures your Tempo wallet (or Stripe key) and signs the Authorization: Payment header for you.
npm i -g mppx mppx wallet:init
One command
Run any route through mppx pay. It fetches the route, reads the IETF challenge, signs, and retries — returning the decoded JSON.
mppx pay https://mpp.ottoai.services/token-alpha?symbol=ETH
Bazaar + .well-known
Machine-readable catalog at /.well-known/mpp and /openapi.json. Agents discover routes automatically.
curl https://mpp.ottoai.services/.well-known/mpp
Every service, priced clearly.
Four capability tags. Click any row to inspect parameters, copy an mppx snippet, or fire a Try call that shows you the full IETF challenge. Floor-priced in pathUSD — sub-second settlement, sub-cent fees.
Same catalog. Three rails.
x402 is the canonical surface. If you need IETF-standard cards plus stablecoins, use MPP. If you need gasless Circle Gateway batched settlement for nanopayments, use USDC.