MPP (Machine Payments Protocol)
MPP, or the Machine Payments Protocol, is a protocol that lets software agents pay servers for API access on a per-request basis, with no human accounts or subscriptions. Like x402, it gives machines a native way to transact. Merit Systems' MPPScan indexes the MPP ecosystem, tracking its servers, agents, transactions, and volume.
Updated June 24, 2026
MPP by the numbers
Live from mppscan- Transactions
- 1.2M
- Total volume
- $146.5K
- Unique senders
- 96.4K
- Unique recipients
- 3.9K
Updated hourly.
How does MPP work?
An agent calls a server's endpoint and pays for that single request instead of holding a subscription or API key. The server meters each call and charges for it, so a machine buys exactly what it needs, when it needs it. The payment and the API call happen together, machine to machine.
Who is behind MPP?
MPP is an open standard, co-authored by Tempo and Stripe. It is open, so any agent, app, or service can implement it.
What is MPPScan?
MPPScan is Merit Systems' explorer for the Machine Payments Protocol, the MPP counterpart to x402scan for x402. It indexes the servers that accept machine payments and tracks the agents, transactions, and volume moving across the network.
| Metric | What it represents |
|---|---|
| Servers | API providers that accept per-request machine payments |
| Agents | The software making and paying for requests |
| Transactions | Individual paid API calls |
| Volume | Total value transacted across the network |
How does MPP relate to x402?
Both MPP and x402 are protocols for machine payments: they let agents pay for API access per request rather than through human accounts. They are part of the same shift toward agent-native payments, and Merit Systems indexes both, x402 through x402scan and MPP through MPPScan.
Frequently Asked Questions
- What does MPP stand for?
- MPP stands for Machine Payments Protocol. It is a protocol that lets software agents pay servers for API access on a per-request basis, without human accounts or subscriptions.
- Is MPP the same as x402?
- Not exactly. Both are protocols for machine payments and share the goal of letting agents pay per request. They are distinct standards, and Merit Systems tracks both through x402scan and MPPScan.
- What is MPPScan?
- MPPScan is Merit Systems' explorer for the Machine Payments Protocol. It indexes MPP servers and tracks the agents, transactions, and volume across the network.
- Can AI agents use MPP?
- Yes. MPP is built for autonomous software. An agent can call a server, pay per request, and receive the result without a human completing a checkout.