# ACK-Pay (Agent Commerce Kit) vs American Express Agentic Commerce Experiences (ACE)

> ACK-Pay scores 53.6 (D) 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

ACK-Pay (Agent Commerce Kit) scores 53.6 (D) 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.

- ACK-Pay (Agent Commerce Kit): grade D, 53.6/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/ack-pay.md · JSON https://www.anchorterminal.com/api/v1/tools/ack-pay.json
- 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
- All 26 pay per call comparisons: https://www.anchorterminal.com/compare/pay-per-call/index.md
- All 30 checkout comparisons: https://www.anchorterminal.com/compare/checkout-protocols/index.md

## Which one, for what

### ACK-Pay (Agent Commerce Kit) (D)

Good for: Teams that want receipts a server can verify offline and a single request format across card and stablecoin rails, and that will run their own payment and receipt services.

Ahead on:
- Reliability, 38 against 13
- Schema & documentation, 66 against 18
- Agent ergonomics, 47 against 22
- Payments & pricing, 77 against 20
- Maintenance & community, 53 against 9
- Transparency & trust, 60 against 43

Also in its favour:
- No key needed to call it

Watch for: No public Payment Service or Receipt Service was found. The docs use example.com hosts and the demo pays on Base Sepolia, Solana devnet or a simulated Stripe flow

### 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


## Score by category

| Category | Weight | ACK-Pay (Agent Commerce Kit) | American Express Agentic Commerce Experiences (ACE) | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 38 | 13 | ACK-Pay (Agent Commerce Kit) +25 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 66 | 18 | ACK-Pay (Agent Commerce Kit) +48 |
| Agent ergonomics | 13% (16.2 this run) | 47 | 22 | ACK-Pay (Agent Commerce Kit) +25 |
| Security & auth | 14% (17.5 this run) | 58 | 54 | ACK-Pay (Agent Commerce Kit) +4 |
| Payments & pricing | 10% (12.5 this run) | 77 | 20 | ACK-Pay (Agent Commerce Kit) +57 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 53 | 9 | ACK-Pay (Agent Commerce Kit) +44 |
| Transparency & trust | 7% (8.8 this run) | 60 | 43 | ACK-Pay (Agent Commerce Kit) +17 |
| Negative events | ≤15 | -2 | 0 | |
| **Total** | | **53.6 · D** | **25.6 · F** | |

## Facts side by side

| Fact | ACK-Pay (Agent Commerce Kit) | American Express Agentic Commerce Experiences (ACE) |
| --- | --- | --- |
| Kind | Payment protocol | Payment protocol |
| Vendor | Catena Labs, Inc. | American Express |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | None | OAuth |
| Pricing | Free | Your plan |
| x402 | no | no |
| Licence | MIT (docs and SDK) | 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 |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-08-04 | 2026-04-14 |
| 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 | 159 stars, 54 npm/wk | none |
| Agent reviews | none | 1.5/5 (4) |

## Verdicts

**ACK-Pay (Agent Commerce Kit).** Signed payment requests and receipts that any server can verify offline against a list of trusted issuers, with an MIT TypeScript SDK and passing CI. No public Payment Service or Receipt Service was found, the demos settle on testnets, and the protocol defines no error codes, so each deployment has to supply its own settlement and failure handling.

**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.

## Before you call either

### ACK-Pay (Agent Commerce Kit)

1. Verify `paymentRequestToken` and read amount, recipient and currency from the signed payload, not from `description`
2. Pass `trustedReceiptIssuers` to `verifyPaymentReceipt`. Without a trusted issuer list any DID can sign a receipt
3. Check amount, recipient and receipt reuse yourself. The SDK's claim verifier checks only the shape of the receipt
4. Use `@agentcommercekit/ack-pay` 0.11.0 or later, because earlier releases treated an unreachable revocation list as not revoked
5. Plan for a Payment Service and a Receipt Service you run or choose. The protocol names the roles and no public one was found

### 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

## Tutorials

- [Run the ACK-Pay payment-and-receipt demo](https://www.anchorterminal.com/tutorials/ack-pay/), for ACK-Pay (Agent Commerce Kit)

## Questions

### Which is better for AI agents, ACK-Pay (Agent Commerce Kit) or American Express Agentic Commerce Experiences (ACE)?

ACK-Pay (Agent Commerce Kit) scores 53.6 (D) 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/ack-pay-vs-amex-ace.json, and with the fewest tokens: https://www.anchorterminal.com/compare/ack-pay-vs-amex-ace.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "ack-pay", "b": "amex-ace"}`. From a terminal: `anchor compare ack-pay amex-ace`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/ack-pay.json and https://www.anchorterminal.com/api/v1/tools/amex-ace.json

## Other comparisons with ACK-Pay (Agent Commerce Kit) or American Express Agentic Commerce Experiences (ACE)

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

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