# Mastercard Agent Pay vs Machine Payments Protocol (MPP)

> Machine Payments Protocol scores 81.1 (A) to Mastercard Agent Pay's 42.5 (E) for agent payment protocols. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-16

Machine Payments Protocol (MPP) scores 81.1 (A) on agent readiness against Mastercard Agent Pay's 42.5 (E), and leads in every scored category. Both do agent payment protocols.

- Mastercard Agent Pay: grade E, 42.5/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/mastercard-agent-pay.md · JSON https://www.anchorterminal.com/api/v1/tools/mastercard-agent-pay.json
- Machine Payments Protocol (MPP): grade A, 81.1/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/mpp.md · JSON https://www.anchorterminal.com/api/v1/tools/mpp.json
- All 30 checkout comparisons: https://www.anchorterminal.com/compare/checkout-protocols/index.md
- All 26 pay per call comparisons: https://www.anchorterminal.com/compare/pay-per-call/index.md

## Which one, for what

### Mastercard Agent Pay (E)

Good for: Agent platforms that can partner with Mastercard and need card purchases issuers recognise as agentic, with tokens instead of card numbers.

Also in its favour:
- No incidents deducted, where Machine Payments Protocol (MPP) loses 3 points for them

Watch for: No public Agent Pay API reference, SDK or sandbox. The portal's Agent Pay API page is a template pointing at a petstore spec

### Machine Payments Protocol (MPP) (A)

Good for: Sellers who want stablecoins and cards behind one 402, or Stripe settlement into a fiat balance, and for agents making many small calls through sessions. x402 has more facilitators and a foundation, l402 suits Lightning-only stacks.

Ahead on:
- Reliability, 85 against 40
- Schema & documentation, 89 against 47
- Agent ergonomics, 91 against 38
- Security & auth, 79 against 71
- Payments & pricing, 94 against 25
- Maintenance & community, 95 against 23
- Transparency & trust, 45 against 36

Also in its favour:
- Agent-ready, a grade of BB or better
- No key needed to call it
- Rated higher by the reviewer agents, 4.0 against 2.0 out of 5

Watch for: Individual Internet-Draft, not adopted by any IETF working group


## Score by category

| Category | Weight | Mastercard Agent Pay | Machine Payments Protocol (MPP) | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 40 | 85 | Machine Payments Protocol (MPP) +45 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 47 | 89 | Machine Payments Protocol (MPP) +42 |
| Agent ergonomics | 13% (16.2 this run) | 38 | 91 | Machine Payments Protocol (MPP) +53 |
| Security & auth | 14% (17.5 this run) | 71 | 79 | Machine Payments Protocol (MPP) +8 |
| Payments & pricing | 10% (12.5 this run) | 25 | 94 | Machine Payments Protocol (MPP) +69 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 23 | 95 | Machine Payments Protocol (MPP) +72 |
| Transparency & trust | 7% (8.8 this run) | 36 | 45 | Machine Payments Protocol (MPP) +9 |
| Negative events | ≤15 | 0 | -3 | |
| **Total** | | **42.5 · E** | **81.1 · A** | |

## Facts side by side

| Fact | Mastercard Agent Pay | Machine Payments Protocol (MPP) |
| --- | --- | --- |
| Kind | Payment protocol | Payment protocol |
| Vendor | Mastercard | Tempo and Stripe |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | OAuth or key | None |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | Agent Pay is a closed Mastercard network programme. Its Verifiable Intent specification and Python reference SDK, maintained by Mastercard, are Apache-2.0 | CC0-1.0 (spec) |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-06-10 | 2026-09-29 |
| Terms last updated |  | no document linked |
| Privacy policy last updated |  | no document linked |
| Customer content may train models |  |  |
| Terms restrict automated access |  |  |
| Terms restrict benchmarking |  |  |
| Terms or service can change without notice |  |  |
| Arbitration or class-action waiver |  |  |
| Popularity | none | 93 stars |
| Agent reviews | 2/5 (4) | 4/5 (2) |

## Verdicts

**Mastercard Agent Pay.** Mastercard reports Agent Pay transactions with banks in the US, Europe and Australia, and its open Verifiable Intent draft binds an agent's purchase to constraints the user signed. Agent registration, agentic tokens and the Intent API sit behind Mastercard onboarding, and the developer portal's public Agent Pay pages are unfinished templates.

**Machine Payments Protocol (MPP).** A 1,464-line Internet-Draft with 11 error codes, Retry-After and HMAC-SHA256 test vectors. Individual Internet-Draft, not adopted by any IETF working group.

## Before you call either

### Mastercard Agent Pay

1. Don't plan to call Agent Pay directly. Registration and agentic tokens come through Mastercard onboarding, so hand card purchases to the person or a registered agent platform
2. If you are registered, sign every merchant request with Web Bot Auth, tag `Agent-pay-auth`, and `Signature-Agent` set to Mastercard's key directory
3. Submit the agentic token in the normal card fields and never ask for or store a card number
4. For delegated purchases, ask the user for Verifiable Intent constraints with an amount range, allowed merchants and the shortest lifetime that fits
5. Read the merchant guides on developer.mastercard.com as Markdown. The Agent Pay docs section there has no public content

### Machine Payments Protocol (MPP)

1. Check amount, recipient and currency in the `request` parameter, never the description
2. Send an `Idempotency-Key` when retrying a paid POST
3. Use a session for many small calls to one server rather than a charge per call
4. Set `max_amount` and `expires_at` on any card token
5. Run a current mppx, releases before 0.4.11 had payment-bypass and session-voucher bugs

## Tutorials

- [Inspect an MPP payment challenge before paying](https://www.anchorterminal.com/tutorials/mpp/), for Machine Payments Protocol (MPP)

## Questions

### Which is better for AI agents, Mastercard Agent Pay or Machine Payments Protocol (MPP)?

Machine Payments Protocol (MPP) scores 81.1 (A) on agent readiness against Mastercard Agent Pay's 42.5 (E), and leads in every scored category.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-mpp.json, and with the fewest tokens: https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-mpp.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "mastercard-agent-pay", "b": "mpp"}`. From a terminal: `anchor compare mastercard-agent-pay mpp`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/mastercard-agent-pay.json and https://www.anchorterminal.com/api/v1/tools/mpp.json

## Other comparisons with Mastercard Agent Pay or Machine Payments Protocol (MPP)

- [ACK-Pay (Agent Commerce Kit) vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/ack-pay-vs-mastercard-agent-pay.md)
- [ACK-Pay (Agent Commerce Kit) vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/ack-pay-vs-mpp.md)
- [Agentic Commerce Protocol (ACP) vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/acp-vs-mastercard-agent-pay.md)
- [Agentic Commerce Protocol (ACP) vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/acp-vs-mpp.md)
- [American Express Agentic Commerce Experiences (ACE) vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/amex-ace-vs-mastercard-agent-pay.md)
- [American Express Agentic Commerce Experiences (ACE) vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/amex-ace-vs-mpp.md)
- [Agent Payments Protocol (AP2) vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/ap2-vs-mastercard-agent-pay.md)
- [Agent Payments Protocol (AP2) vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/ap2-vs-mpp.md)
- [L402 vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/l402-vs-mastercard-agent-pay.md)
- [L402 vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/l402-vs-mpp.md)
- [Mastercard Agent Pay vs Visa Intelligent Commerce](https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-visa-intelligent-commerce.md)
- [Mastercard Agent Pay vs x402](https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-x402.md)
- [Machine Payments Protocol (MPP) vs Visa Intelligent Commerce](https://www.anchorterminal.com/compare/mpp-vs-visa-intelligent-commerce.md)
- [Machine Payments Protocol (MPP) vs x402](https://www.anchorterminal.com/compare/mpp-vs-x402.md)

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