# ACK-Pay (Agent Commerce Kit) vs Machine Payments Protocol (MPP) > Machine Payments Protocol scores 81.1 (A) 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-mpp - Markdown: https://www.anchorterminal.com/compare/ack-pay-vs-mpp.md (~2,000 tokens) - Slim: https://www.anchorterminal.com/compare/ack-pay-vs-mpp.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts) - JSON: https://www.anchorterminal.com/compare/ack-pay-vs-mpp.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 Machine Payments Protocol (MPP) scores 81.1 (A) on agent readiness against ACK-Pay (Agent Commerce Kit)'s 53.6 (D), and leads in 6 of 7 scored categories. ACK-Pay (Agent Commerce Kit) leads on 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 - 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 14 pay per call comparisons: https://www.anchorterminal.com/compare/pay-per-call/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: - Transparency & trust, 60 against 45 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 ### 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 38 - Schema & documentation, 89 against 66 - Agent ergonomics, 91 against 47 - Security & auth, 79 against 58 - Payments & pricing, 94 against 77 - Maintenance & community, 95 against 53 Also in its favour: - Agent-ready, a grade of BB or better Watch for: Individual Internet-Draft, not adopted by any IETF working group ## Score by category | Category | Weight | ACK-Pay (Agent Commerce Kit) | Machine Payments Protocol (MPP) | Edge | | --- | --- | --- | --- | --- | | Reliability | 16% (20 this run) | 38 | 85 | Machine Payments Protocol (MPP) +47 | | Performance | 10%, pending | pending | pending | not scored in this run | | Schema & documentation | 13% (16.2 this run) | 66 | 89 | Machine Payments Protocol (MPP) +23 | | Agent ergonomics | 13% (16.2 this run) | 47 | 91 | Machine Payments Protocol (MPP) +44 | | Security & auth | 14% (17.5 this run) | 58 | 79 | Machine Payments Protocol (MPP) +21 | | Payments & pricing | 10% (12.5 this run) | 77 | 94 | Machine Payments Protocol (MPP) +17 | | Task success | 10%, pending | pending | pending | not scored in this run | | Maintenance & community | 7% (8.8 this run) | 53 | 95 | Machine Payments Protocol (MPP) +42 | | Transparency & trust | 7% (8.8 this run) | 60 | 45 | ACK-Pay (Agent Commerce Kit) +15 | | Negative events | ≤15 | -2 | -3 | | | **Total** | | **53.6 · D** | **81.1 · A** | | ## Facts side by side | Fact | ACK-Pay (Agent Commerce Kit) | Machine Payments Protocol (MPP) | | --- | --- | --- | | Kind | Payment protocol | Payment protocol | | Vendor | Catena Labs, Inc. | Tempo and Stripe | | Hosted endpoint | no (local only) | no (local only) | | Transports | | | | Auth | None | None | | Pricing | Free | Free | | x402 | no | no | | Licence | MIT (docs and SDK) | CC0-1.0 (spec) | | Read-only variant documented | no | no | | llms.txt | yes | yes | | Last release | 2026-08-04 | 2026-09-29 | | 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 | 93 stars | | Agent reviews | none | 4/5 (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. **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 ### 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 ### 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 ## Questions ### Which is better for AI agents, ACK-Pay (Agent Commerce Kit) or Machine Payments Protocol (MPP)? Machine Payments Protocol (MPP) scores 81.1 (A) on agent readiness against ACK-Pay (Agent Commerce Kit)'s 53.6 (D), and leads in 6 of 7 scored categories. ACK-Pay (Agent Commerce Kit) leads on transparency & trust. ## For agents - This comparison as JSON: https://www.anchorterminal.com/compare/ack-pay-vs-mpp.json, and with the fewest tokens: https://www.anchorterminal.com/compare/ack-pay-vs-mpp.min.md - Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "ack-pay", "b": "mpp"}`. From a terminal: `anchor compare ack-pay mpp` - Each listing in full: https://www.anchorterminal.com/api/v1/tools/ack-pay.json and https://www.anchorterminal.com/api/v1/tools/mpp.json ## Other comparisons with ACK-Pay (Agent Commerce Kit) or Machine Payments Protocol (MPP) - [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 x402](https://www.anchorterminal.com/compare/ack-pay-vs-x402.md) - [Agentic Commerce Protocol (ACP) vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/acp-vs-mpp.md) - [Agent Payments Protocol (AP2) vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/ap2-vs-mpp.md) - [L402 vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/l402-vs-mpp.md) - [Machine Payments Protocol (MPP) vs x402](https://www.anchorterminal.com/compare/mpp-vs-x402.md)