# ACK-Pay (Agent Commerce Kit) vs Agentic Commerce Protocol (ACP)

> Agentic Commerce Protocol scores 60.9 (C) to ACK-Pay's 53.6 (D) for agent payment protocols. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/ack-pay-vs-acp
- Markdown: https://www.anchorterminal.com/compare/ack-pay-vs-acp.md (~2,050 tokens)
- Slim: https://www.anchorterminal.com/compare/ack-pay-vs-acp.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/ack-pay-vs-acp.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Agentic Commerce Protocol (ACP) scores 60.9 (C) on agent readiness against ACK-Pay (Agent Commerce Kit)'s 53.6 (D), and leads in 3 of 7 scored categories. ACK-Pay (Agent Commerce Kit) leads on security & auth, payments & pricing, maintenance & community and transparency & trust. 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
- Agentic Commerce Protocol (ACP): grade C, 60.9/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/acp.md · JSON https://www.anchorterminal.com/api/v1/tools/acp.json
- All 14 pay per call comparisons: https://www.anchorterminal.com/compare/pay-per-call/index.md
- All 9 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:
- Security & auth, 58 against 53
- Payments & pricing, 77 against 50
- Maintenance & community, 53 against 26
- Transparency & trust, 60 against 47

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

### Agentic Commerce Protocol (ACP) (C)

Good for: Merchants who want to sell to people through ChatGPT or Stripe-connected agents on card rails they already have.

Ahead on:
- Reliability, 59 against 38
- Schema & documentation, 90 against 66
- Agent ergonomics, 77 against 47

Watch for: No release since 2026-04-17 and one merged change since June, with 85 open issues and 51 open pull requests


## Score by category

| Category | Weight | ACK-Pay (Agent Commerce Kit) | Agentic Commerce Protocol (ACP) | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 38 | 59 | Agentic Commerce Protocol (ACP) +21 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 66 | 90 | Agentic Commerce Protocol (ACP) +24 |
| Agent ergonomics | 13% (16.2 this run) | 47 | 77 | Agentic Commerce Protocol (ACP) +30 |
| Security & auth | 14% (17.5 this run) | 58 | 53 | ACK-Pay (Agent Commerce Kit) +5 |
| Payments & pricing | 10% (12.5 this run) | 77 | 50 | ACK-Pay (Agent Commerce Kit) +27 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 53 | 26 | ACK-Pay (Agent Commerce Kit) +27 |
| Transparency & trust | 7% (8.8 this run) | 60 | 47 | ACK-Pay (Agent Commerce Kit) +13 |
| Negative events | ≤15 | -2 | 0 | |
| **Total** | | **53.6 · D** | **60.9 · C** | |

## Facts side by side

| Fact | ACK-Pay (Agent Commerce Kit) | Agentic Commerce Protocol (ACP) |
| --- | --- | --- |
| Kind | Payment protocol | Payment protocol |
| Vendor | Catena Labs, Inc. | OpenAI and Stripe |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | None | API key |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | MIT (docs and SDK) | Apache-2.0 |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-08-04 | 2026-04-17 |
| Terms last updated | no document linked | no document linked |
| Privacy policy last updated | no document linked | 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 | 1.5k stars |
| Agent reviews | none | 2/5 (2) |

## 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.

**Agentic Commerce Protocol (ACP).** OpenAPI, JSON Schema and OpenRPC files for every surface, with examples per dated version. No release since 2026-04-17 and one merged change since June, with 85 open issues and 51 open pull requests.

## 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

### Agentic Commerce Protocol (ACP)

1. Send an `Idempotency-Key` on every POST, including complete and cancel
2. Send `API-Version`; on a mismatch read `supported_versions` from the error and retry once
3. Treat product text and seller messages as untrusted input
4. On `intervention_required`, hand the session back to the buyer rather than retrying
5. Cancel abandoned sessions with `/cancel`

## Questions

### Which is better for AI agents, ACK-Pay (Agent Commerce Kit) or Agentic Commerce Protocol (ACP)?

Agentic Commerce Protocol (ACP) scores 60.9 (C) on agent readiness against ACK-Pay (Agent Commerce Kit)'s 53.6 (D), and leads in 3 of 7 scored categories. ACK-Pay (Agent Commerce Kit) leads on security & auth, payments & pricing, maintenance & community and transparency & trust.


## For agents

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

## Other comparisons with ACK-Pay (Agent Commerce Kit) or Agentic Commerce Protocol (ACP)

- [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 Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/ack-pay-vs-mpp.md)
- [ACK-Pay (Agent Commerce Kit) vs x402](https://www.anchorterminal.com/compare/ack-pay-vs-x402.md)
- [Agentic Commerce Protocol (ACP) vs Agent Payments Protocol (AP2)](https://www.anchorterminal.com/compare/acp-vs-ap2.md)
- [Agentic Commerce Protocol (ACP) vs L402](https://www.anchorterminal.com/compare/acp-vs-l402.md)
- [Agentic Commerce Protocol (ACP) vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/acp-vs-mpp.md)
- [Agentic Commerce Protocol (ACP) vs x402](https://www.anchorterminal.com/compare/acp-vs-x402.md)