Built on Machine Payments Protocol

Spending Guardrails
for Autonomous AI Agents

Per-agent budgets, auto-stop, and full audit trails. Control what your agents spend — across Tempo and Solana.

server.ts
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import { Mppx, tempo } from 'mppx/express'

// Point feePayer to MPP Gate facilitator
const mppx = Mppx.create({
secretKey: process.env.MPP_SECRET_KEY,
methods: [tempo({
currency: '0x20c...8b50',
recipient: '0xYourAddress',
feePayerUrl: 'https://facilitator.mppgate.com',
})],
})

// Gate any endpoint behind a micropayment
app.post('/api/weather',
mppx.charge({ amount: '0.001' }),
async (req, res) => {
// Payment verified — serve the request
res.json({ weather: 'Sunny, 24°C' })
}
)

Core Features

Per-Agent Budgets

Set spending caps per agent or session. Know exactly how much each agent can spend before it stops.

Auto-Stop

Coming Soon

Agents are halted automatically when they hit their budget. No surprise bills, no runaway costs.

Audit Trail

Coming Soon

Full log of every payment — which agent, when, how much, on which chain. Complete visibility.

Fee Sponsorship

Co-sign transactions as a fee payer so agents never need to hold gas tokens. Just stablecoins.

Multi-Chain

Supports Tempo and Solana as payment rails. Control agent spending regardless of which chain they use.

API Proxy

Coming Soon

Route OpenAI, Anthropic, and other API calls through MPP Gate. Pay-per-call with spending controls.

The Problem

AI agents shouldn't spend without limits

Autonomous agents can make payments on their own. Without guardrails, developers face surprise bills, runaway costs, and zero visibility into what was spent.

Without MPP Gate

  • No spending limits — agents can drain wallets
  • No visibility into per-agent costs
  • Every agent needs gas tokens funded manually
  • No audit trail when things go wrong

With MPP Gate

  • Per-agent budgets with auto-stop
  • Full audit trail — every payment logged
  • Gas fees sponsored — agents only need stablecoins
  • Multi-chain: Tempo + Solana from one control plane

Where MPP Gate sits

Your AI Agents
MPP GATE
Budgets · Auto-stop · Audit · Fee payer
MPP Protocol
Tempo
Solana

The Flow

How MPP Gate controls agent payments

Every agent payment flows through MPP Gate. Budget checks, fee sponsorship, and audit logging happen automatically.

1
Agent

Agent requests a paid API

Your AI agent sends a request to an MPP-gated endpoint. The agent has been assigned a budget and API key through MPP Gate.

POST /api/weather → { city: 'Tokyo' }
2
Server

402 Payment Required

The API responds with a payment challenge — how much, what currency, and where to pay.

402 ← WWW-Authenticate: Tempo amount=1000, currency=USDC
3
MPP Gate

Budget check & fee sponsorship

MPP Gate checks the agent's remaining budget. If approved, it co-signs the transaction as fee payer (covering gas) and broadcasts it. The payment is logged to the audit trail.

✓ Budget: $4.20 remaining → co-sign → broadcast → log
4
Agent

Retry with payment proof

The agent retries the original request with payment credentials attached.

POST /api/weather + Authorization: Tempo credential=0xabc...
5
Server

200 OK — Serve the response

Server verifies the payment on-chain and serves the resource. The developer can see this transaction in the MPP Gate audit trail.

200 ← { weather: 'Sunny, 24°C in Tokyo' }

Payment Rails

Tempo
Supported
Solana
Supported