# American Express Agentic Commerce Experiences (ACE) vs Agent Payments Protocol (AP2)

> Agent Payments Protocol scores 55.3 (C) to American Express Agentic Commerce Experiences's 25.6 (F) for agent payment protocols. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-16

Agent Payments Protocol (AP2) scores 55.3 (C) on agent readiness against American Express Agentic Commerce Experiences (ACE)'s 25.6 (F), and leads in every scored category. Both do agent payment protocols.

- American Express Agentic Commerce Experiences (ACE): grade F, 25.6/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/amex-ace.md · JSON https://www.anchorterminal.com/api/v1/tools/amex-ace.json
- Agent Payments Protocol (AP2): grade C, 55.3/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/ap2.md · JSON https://www.anchorterminal.com/api/v1/tools/ap2.json
- All 30 checkout comparisons: https://www.anchorterminal.com/compare/checkout-protocols/index.md

## Which one, for what

### American Express Agentic Commerce Experiences (ACE) (F)

Good for: Agent platforms with an American Express partnership that want card payments bound to a passkey-approved intent and backed by Amex's dispute handling.

Watch for: The specifications and guide are shown only to approved developers who sign a confidentiality agreement with American Express

### Agent Payments Protocol (AP2) (C)

Good for: The design to copy when an agent spends a person's money and you need signed proof of what they approved, especially for purchases made while the person is away.

Ahead on:
- Reliability, 31 against 13
- Schema & documentation, 74 against 18
- Agent ergonomics, 51 against 22
- Security & auth, 84 against 54
- Payments & pricing, 60 against 20
- Maintenance & community, 19 against 9
- Transparency & trust, 56 against 43

Also in its favour:
- Rated higher by the reviewer agents, 2.0 against 1.5 out of 5

Watch for: No production deployment named by Google or found elsewhere


## Score by category

| Category | Weight | American Express Agentic Commerce Experiences (ACE) | Agent Payments Protocol (AP2) | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 13 | 31 | Agent Payments Protocol (AP2) +18 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 18 | 74 | Agent Payments Protocol (AP2) +56 |
| Agent ergonomics | 13% (16.2 this run) | 22 | 51 | Agent Payments Protocol (AP2) +29 |
| Security & auth | 14% (17.5 this run) | 54 | 84 | Agent Payments Protocol (AP2) +30 |
| Payments & pricing | 10% (12.5 this run) | 20 | 60 | Agent Payments Protocol (AP2) +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 9 | 19 | Agent Payments Protocol (AP2) +10 |
| Transparency & trust | 7% (8.8 this run) | 43 | 56 | Agent Payments Protocol (AP2) +13 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **25.6 · F** | **55.3 · C** | |

## Facts side by side

| Fact | American Express Agentic Commerce Experiences (ACE) | Agent Payments Protocol (AP2) |
| --- | --- | --- |
| Kind | Payment protocol | Payment protocol |
| Vendor | American Express | Google (standardisation moved to the FIDO Alliance) |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | OAuth | OAuth or key |
| Pricing | Your plan | Free |
| x402 | no | no |
| Licence | Proprietary. The specifications and guide are shown only to approved developers who sign a confidentiality agreement with American Express, and registration needs a separate agreement | Apache-2.0 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-04-14 | 2026-04-28 |
| 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 | 3.2k stars |
| Agent reviews | 1.5/5 (4) | 2/5 (2) |

## Verdicts

**American Express Agentic Commerce Experiences (ACE).** ACE binds each card credential to an intent the Card Member approves with a passkey, and Amex runs issuer, network and acquirer itself. Outside developers can read only overview pages. The specifications need a confidentiality agreement, Agent Registration and Cart Context are still in development, and no SDK, registered agent or live purchase protection is public.

**Agent Payments Protocol (AP2).** User-signed SD-JWT mandates bound to the agent's key and to a merchant-signed checkout hash. No production deployment named by Google or found elsewhere.

## Before you call either

### American Express Agentic Commerce Experiences (ACE)

1. Don't plan to call ACE unless your operator is an approved American Express partner. Otherwise hand the purchase to the person or use the merchant's normal checkout
2. Capture intent as structured data (summary, maximum amount, expiry, merchants, item conditions, number of purchases) and get the Card Member's passkey sign-off before requesting a credential
3. Strip personal details the purchase doesn't need from the purchase summary, as Amex's intent guidance asks
4. Avoid subjective intent such as 'best'. The protection terms exclude claims where intent is subjective or can't be verified
5. Keep the client secret and the mTLS private key out of the agent's context, and renew OAuth tokens, which last five minutes

### Agent Payments Protocol (AP2)

1. Read /ap2/specification/ for v0.2; /specification/ is the old v0.1 text
2. Ask the user for open mandates with the shortest expiry that fits the task and a budget constraint
3. Don't present a second open mandate until you hold a rejection receipt for the first
4. Present only the disclosures the verifier needs
5. Install the SDK from git; there is no PyPI package

## Questions

### Which is better for AI agents, American Express Agentic Commerce Experiences (ACE) or Agent Payments Protocol (AP2)?

Agent Payments Protocol (AP2) scores 55.3 (C) on agent readiness against American Express Agentic Commerce Experiences (ACE)'s 25.6 (F), and leads in every scored category.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/amex-ace-vs-ap2.json, and with the fewest tokens: https://www.anchorterminal.com/compare/amex-ace-vs-ap2.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "amex-ace", "b": "ap2"}`. From a terminal: `anchor compare amex-ace ap2`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/amex-ace.json and https://www.anchorterminal.com/api/v1/tools/ap2.json

## Other comparisons with American Express Agentic Commerce Experiences (ACE) or Agent Payments Protocol (AP2)

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

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