MPP Payment Protocol

MPP (Machine Payment Protocol) is a payment protocol designed for AI agents and automated systems. It is the superset of x402, supporting both Tempo stablecoin payments and Stripe card payments in a single unified flow.

Unlike x402 which only supports on-chain USDC, MPP adds Tempo network stablecoins and traditional card payments as additional options.

How It Works

Detailed Flow

Agent calls GET /mpp/purchase?plan=<plan> without payment credentials
MPP service returns 402 with a WWW-Authenticate: Payment challenge containing amount, currency, and recipient
Agent signs the payment using Tempo Wallet or Stripe
Agent retries the purchase request with Authorization: Payment credential
MPP service verifies payment, creates a subscription, and returns an API Key

Supported Payment Methods

Method	Network	Currency	Gas Fee	Best For
Tempo	Tempo (chain ID 4217)	USDC.e (ERC-20)	Free (gas in stablecoin)	AI agents, no ETH needed
Stripe	Traditional	USD (card)	N/A	Agents with card access, no crypto needed

Tempo payments do not require native gas tokens — gas is paid in the stablecoin directly. This makes it ideal for AI agents that only hold stablecoins.

API Endpoints

Endpoint	Method	Description
`/mpp/purchase?plan=<plan>`	GET / POST	Purchase a subscription via MPP
`/mpp/pricing`	GET	List available plans and payment methods
`/mpp/health`	GET	Health check

Pricing Response

curl https://api.chainstream.io/mpp/pricing

{
  "plans": [
    { "name": "nano", "priceUsd": 5, "quotaTotal": 500000, "durationDays": 30 },
    { "name": "starter", "priceUsd": 199, "quotaTotal": 10000000, "durationDays": 30 }
  ],
  "currency": "USD",
  "paymentMethods": ["tempo", "stripe"],
  "note": "Prices in USD. Pay via MPP (Tempo stablecoin or Stripe card)."
}

Purchase Response (Success)

{
  "status": "ok",
  "plan": "nano",
  "expiresAt": "2026-04-25T12:00:00.000Z",
  "apiKey": "cs_live_..."
}

CLI Usage

The ChainStream CLI supports MPP as a payment option during the auto-purchase flow:

chainstream token info --chain sol --address So11111111111111111111111111111111111111112
# → 402 → plan selection → choose "MPP Tempo" → payment → API Key saved

For agents without a ChainStream wallet, the CLI prints the Tempo command:

tempo request "https://api.chainstream.io/mpp/purchase?plan=nano"

Manual Integration (Tempo Wallet)

Setup

Install the Tempo Wallet CLI and log in (one-time passkey authentication via browser):

curl -fsSL https://tempo.xyz/install | bash
tempo wallet login

Tempo Wallet uses passkey (WebAuthn) authentication. The first setup requires a browser interaction. After that, the session persists and agent operations work without further browser interaction.

Purchase

# Check your balance
tempo wallet balance

# Purchase a plan (auto-handles 402 → sign → retry)
tempo request "https://api.chainstream.io/mpp/purchase?plan=nano"

The Tempo CLI handles the WWW-Authenticate: Payment challenge automatically, signs the transaction, and returns the API Key on success.

Compatible Wallets

Tempo is EVM-compatible (chain ID 4217). Any wallet holding USDC.e on Tempo works:

Tempo Wallet CLI (tempo request) — recommended, passkey auth, built-in MPP support
Any EVM wallet (MetaMask, Coinbase CDP, Privy) — add Tempo as custom network

MPP vs x402

	MPP	x402
Payment methods	Tempo stablecoin + Stripe card	On-chain USDC only
Networks	Tempo (chain ID 4217) + Stripe	Base (EVM) + Solana
Gas fee	Free (Tempo) / N/A (Stripe)	Free (facilitator)
Requires crypto wallet	No (Stripe option available)	Yes
Purchase endpoint	`/mpp/purchase`	`/x402/purchase`
Protocol	MPP (HTTP 402)	x402 protocol
Best for	Agents without crypto wallets	Agents with USDC on Base/Solana

Data Products

Access Methods

AI Agents

Compliance (KYT/KYA)

Tutorials

Recipes

Platform

Ecosystem

Reference

How It Works

Detailed Flow

Supported Payment Methods

API Endpoints

Pricing Response

Purchase Response (Success)

CLI Usage

Manual Integration (Tempo Wallet)

Setup

Purchase

Compatible Wallets

MPP vs x402

Next Steps

x402 Payment Protocol

Billing & Units

​How It Works

​Detailed Flow

​Supported Payment Methods

​API Endpoints

​Pricing Response

​Purchase Response (Success)

​CLI Usage

​Manual Integration (Tempo Wallet)

​Setup

​Purchase

​Compatible Wallets

​MPP vs x402

​Next Steps

x402 Payment Protocol

Billing & Units

How It Works

Detailed Flow

Supported Payment Methods

API Endpoints

Pricing Response

Purchase Response (Success)

CLI Usage

Manual Integration (Tempo Wallet)

Setup

Purchase

Compatible Wallets

MPP vs x402

Next Steps