MPP: Machine Payments Protocol
Christian Pickett
Co-founder
Today we're excited to announce our partnership with Tempo to bring the Machine Payments Protocol (MPP) to Orthogonal. MPP is a superset of x402 that adds multi-method payments, sessions, streaming, and an IETF-track standard. Your agents can now pay for API calls inline using stablecoins, cards, or Bitcoin.
What is Tempo?
Tempo is a Layer 1 blockchain purpose-built for payments, developed in partnership with Stripe and Paradigm. Unlike general-purpose chains designed for trading, Tempo is optimized for real-world stablecoin transactions at scale.
Key features:
- Sub-second finality: Blocks finalize in ~0.6 seconds with no re-orgs. Settlement certainty that matches existing financial systems.
- Stablecoin-native gas: Pay fees in USD stablecoins. No volatile gas tokens, predictable costs.
- Dedicated payment lanes: Guaranteed blockspace for payments at the protocol level. Fees stay low even when network activity spikes.
- Smart accounts: Programmable wallets with gas sponsorship, batch transactions, scheduled payments, and passkey auth.
- Privacy: Opt-in confidential transactions with the auditability compliance requires.
What is MPP?
MPP (Machine Payments Protocol) is the open standard for machine-to-machine payments, co-authored by Tempo and Stripe. It standardizes HTTP 402 so agents and services can exchange payments in the same HTTP request.
When a server requires payment, it returns a 402 with a challenge describing the price, accepted methods, and expiration. The client signs a credential, attaches it to the retry, and the server verifies payment and returns the response with a receipt. Two round-trips: the initial 402 challenge, then the paid retry.
MPP supports multiple payment rails out of the box: Tempo stablecoins, Stripe cards, Lightning Bitcoin, EVM tokens, Solana, Stellar, and more. Visa extended MPP to support card-based payments. Lightspark added Lightning Network support.
Using MPP on Orthogonal
Every API on Orthogonal is now accessible via MPP at mpp.orthogonal.com. Your agents can pay per request using a wallet instead of an API key.
Pay for an API Call with MPP
import { privateKeyToAccount } from "viem/accounts";
import { Mppx, tempo } from "mppx/client";
// Set up automatic 402 handling with your Tempo wallet
Mppx.create({
methods: [tempo({ account: privateKeyToAccount("0x...") })],
});
// Global fetch now handles 402 challenges automatically
const response = await fetch(
"https://mpp.orthogonal.com/didit/v3/email/send",
{
method: "POST",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({
email: "user@example.com",
}),
}
);
const data = await response.json();
console.log(data);The mppx client handles the 402 challenge automatically: it intercepts the payment request, signs a credential with your wallet, and retries with proof of payment. You get back the API response.
Pay-as-You-Go Sessions
For high-frequency workflows, open a payment session. You deposit once into an on-chain escrow, then send signed off-chain vouchers with each request. Only two on-chain transactions total: open and close. Everything in between is just a signed message.
import { tempo } from "mppx/client";
import { createClient, http } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { Chain } from "viem/tempo";
const account = privateKeyToAccount("0x...");
const client = createClient({
account,
chain: Chain.mainnet,
transport: http(),
});
// Lock 1 USD into a payment channel. Unused deposit is refunded on close.
const session = tempo.session.manager({
client,
maxDeposit: "1",
});
for (const lead of leads) {
const result = await session.fetch(
"https://mpp.orthogonal.com/apollo/v1/people/match",
{
method: "POST",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({ email: lead.email }),
}
);
// Each request sends an off-chain voucher — no gas, no on-chain tx
}
// Close the channel. Server settles on-chain, unused deposit refunded.
await session.close();Multiple Payment Methods
Pay with stablecoins, cards, or Bitcoin on a single endpoint.
import { privateKeyToAccount } from "viem/accounts";
import { Mppx, tempo, stripe } from "mppx/client";
import { spark } from "@buildonspark/lightning-mpp-sdk/client";
Mppx.create({
methods: [
tempo({ account: privateKeyToAccount("0x...") }),
stripe({ paymentToken: "spt_..." }),
spark.charge({ mnemonic: process.env.MNEMONIC }),
],
});
// Client picks the best available method automatically
const response = await fetch(
"https://mpp.orthogonal.com/coresignal/v1/enrich",
{
method: "POST",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({
linkedin_url: "https://linkedin.com/in/janedoe",
}),
}
);Use Cases
Zero-Config API Access
New developers and agents can access any Orthogonal API immediately. No sign-up forms, no API key provisioning. Attach a wallet and start making requests.
Autonomous Agent Workflows
Agents running multi-step workflows across multiple APIs can use a single wallet for all of them. One payment method, many services, no credential management per provider.
MCP Server Monetization
If you're building MCP tools, MPP lets you charge per tool call with stablecoins. No Stripe integration, no billing portal, no invoicing. A few lines of middleware.
Why We Partnered with Tempo
Tempo is building the payments infrastructure that agentic commerce needs. A purpose-built L1 with sub-second finality, stablecoin-native gas, and dedicated payment lanes means agents get deterministic settlement without the latency and gas volatility of general-purpose chains. MPP, co-authored by Tempo and Stripe, gives agents a standard way to pay for any service over HTTP, with support for one-shot charges, sessions, streaming, and multiple payment rails. By integrating MPP into Orthogonal at mpp.orthogonal.com, every API on our platform is accessible to any agent with a wallet.
Try It Today
MPP is live on Orthogonal now. All of our endpoints are discoverable on the MPP Discover Service. Set up a Tempo wallet, point your agent at mpp.orthogonal.com, and start making paid API calls with zero configuration.