{ "data": { "a": { "slug": "ack-pay", "name": "ACK-Pay (Agent Commerce Kit)", "vendor": "Catena Labs, Inc.", "vendorUrl": "https://www.agentcommercekit.com", "kind": "protocol", "category": "pay-per-call", "summary": "ACK-Pay is the open payment protocol in Agent Commerce Kit from Catena Labs. A server returns a signed Payment Request, the client pays through a Payment Service and retries with a receipt issued as a W3C Verifiable Credential.", "url": "https://www.anchorterminal.com/tools/ack-pay", "markdownUrl": "https://www.anchorterminal.com/tools/ack-pay.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/ack-pay.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/ack-pay.json", "repo": "https://github.com/agentcommercekit/ack", "license": "MIT (docs and SDK)", "transports": [], "packages": [ { "registry": "npm", "name": "@agentcommercekit/ack-pay" }, { "registry": "npm", "name": "agentcommercekit" } ], "auth": "none", "authNotes": "No account or key. Servers sign Payment Requests with a key bound to a DID, and Receipt Services sign receipts that servers check against their own list of trusted issuer DIDs. Identity checks between parties can use ACK-ID.", "pricing": "free", "pricingNotes": "No protocol fee, and the SDK is MIT with nothing to buy. Settlement costs depend on the Payment Service and rail a deployment chooses. The docs say conversion and bridging fees should be shown to the client. No public Payment Service with published prices was found.", "priceSummary": "Free", "where": "spec", "x402": { "level": "no", "evidence": "A payment protocol, not a tool that accepts payment. The docs describe x402 as fitting the ACK-Pay pattern and list acting as an x402 facilitator as planned research (checked 2026-10-09).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 159, "npmWeekly": 54, "pypiWeekly": null, "asOf": "2026-10-09" }, "docsUrl": "https://www.agentcommercekit.com/ack-pay/introduction", "llmsTxt": "https://www.agentcommercekit.com/llms.txt", "capabilities": [ "payments.protocol", "payments.stablecoin" ], "tags": [ "protocol", "verifiable-credentials", "did", "receipts", "typescript", "mit", "llms-txt" ], "lastRelease": "2026-08-04", "graded": true, "anchor": { "graded": true, "score": 53.6, "grade": "D", "agentReady": false, "rank": 0, "ranked": false, "notRankedWhy": "A protocol, graded on the same scale but not ranked against tools", "rankOf": 1098, "categoryRank": 4, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 47, "maintenance": 53, "payments": 77, "reliability": 38, "schema": 66, "security": 58, "transparency": 60 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-09" }, "negative": -2, "negativeNotes": [ "2026-08-04, @agentcommercekit/ack-pay 0.11.0 fixed a revocation check that treated any failure to fetch or parse the status list as not revoked, so `verifyPaymentReceipt` accepted revoked credentials. The changelog describes the flaw in full and the repository has no published advisory. Fixed and documented, so we deduct 2 (https://github.com/agentcommercekit/ack/blob/main/packages/ack-pay/CHANGELOG.md, https://github.com/agentcommercekit/ack/security/advisories)" ], "verdict": "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.", "bestFor": "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.", "strengths": [ "Receipts are W3C Verifiable Credentials signed by a Receipt Service, so a server checks payment without calling the payment system", "One Payment Request can list several options, such as USDC on Base and a card payment through Stripe, each with its own Payment Service", "Docs and code are MIT, with llms.txt and a Markdown copy of every docs page", "The SDK exports Valibot and Zod schemas for the request, the option and the receipt claim", "CI builds, lints and tests on every push, and the last five runs on main on the page read passed" ], "weaknesses": [ "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", "The protocol defines no error codes, idempotency key or retry header. The operations page tells implementers to design their own", "One SDK, in TypeScript, at 0.11.0. One release in the last 90 days, with nine changesets waiting on main, including a receipt option check", "0.11.0 fixed a revocation check that accepted revoked credentials when the status list was unreachable. No GitHub advisory was published", "Open issue 222 of 21 September 2026 reports that `expiresAt` on a Payment Request is never enforced", "No terms, privacy policy, status page or security.txt on agentcommercekit.com" ], "agentNotes": [ "Verify `paymentRequestToken` and read amount, recipient and currency from the signed payload, not from `description`", "Pass `trustedReceiptIssuers` to `verifyPaymentReceipt`. Without a trusted issuer list any DID can sign a receipt", "Check amount, recipient and receipt reuse yourself. The SDK's claim verifier checks only the shape of the receipt", "Use `@agentcommercekit/ack-pay` 0.11.0 or later, because earlier releases treated an unreachable revocation list as not revoked", "Plan for a Payment Service and a Receipt Service you run or choose. The protocol names the roles and no public one was found" ], "metrics": { "kind": "spec", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "D", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 53.6 } ], "editorialScores": { "ergonomics": 47, "maintenance": 53, "payments": 77, "reliability": 38, "schema": 66, "security": 58, "transparency": 63 }, "provenanceScore": 57 }, "connect": { "install": "npm i @agentcommercekit/ack-pay" }, "letme": { "capability": "https://letme.dev/payments.protocol", "tool": "https://letme.dev/ack-pay" }, "area": "payments", "provenance": { "legalEntity": "Catena Labs, Inc.", "domain": "agentcommercekit.com", "domainRegistered": "2025-05-02", "domainNote": "The docs site names no legal entity. Catena Labs, Inc. is the copyright holder in the repository's LICENCE file and the author in the package manifests. No terms or privacy policy were found for the docs site, so the MIT licence stands in.", "endpointOnVendorDomain": null, "terms": "", "privacy": "", "statusPage": "", "changelog": "https://github.com/agentcommercekit/ack/blob/main/packages/ack-pay/CHANGELOG.md", "securityTxt": "none", "checked": "2026-10-09", "score": 57 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/ack-pay.json", "live": { "slug": "ack-pay", "versions": [ { "registry": "github", "name": "agentcommercekit/ack", "version": "agentcommercekit@0.11.0", "released": "2026-08-04", "seenAt": "2026-10-16T00:32:37.714574551Z" }, { "registry": "npm", "name": "@agentcommercekit/ack-pay", "version": "0.11.0", "seenAt": "2026-10-16T00:32:35.499501628Z" }, { "registry": "npm", "name": "agentcommercekit", "version": "0.11.0", "seenAt": "2026-10-16T00:32:36.306969323Z" } ], "githubStars": 158, "npmWeekly": 751, "securityTxt": { "url": "https://agentcommercekit.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-15T15:48:51.791292911Z" }, "llmsTxt": { "url": "https://www.agentcommercekit.com/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-16T14:18:12.984100824Z" }, "domain": { "domain": "agentcommercekit.com", "registered": "2025-05-02", "source": "https://rdap.verisign.com/com/v1/domain/agentcommercekit.com", "checkedAt": "2026-10-11T13:16:56.352355321Z" }, "pages": [ { "url": "https://raw.githubusercontent.com/agentcommercekit/ack/main/packages/ack-pay/CHANGELOG.md", "kind": "changelog", "status": 304, "checkedAt": "2026-10-15T22:03:21.268192986Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "a86c2ee19456" } ], "updatedAt": "2026-10-16T14:18:12.984100824Z" } }, "answer": "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.", "b": { "slug": "amex-ace", "name": "American Express Agentic Commerce Experiences (ACE)", "vendor": "American Express", "vendorUrl": "https://www.americanexpress.com/en-us/company/agentic-commerce/", "kind": "protocol", "category": "checkout-protocols", "summary": "American Express's Agentic Commerce Experiences (ACE) developer kit lets verified AI agents pay with scoped, tokenised Amex card credentials against a purchase intent the Card Member approves. Access needs an application and agreements with American Express.", "url": "https://www.anchorterminal.com/tools/amex-ace", "markdownUrl": "https://www.anchorterminal.com/tools/amex-ace.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/amex-ace.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/amex-ace.json", "license": "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", "transports": [], "packages": [], "auth": "oauth", "authNotes": "Partners call the ACE APIs with an OAuth 2.0 client credentials token, obtained with a JWT client assertion signed with the project's client secret, over mutual TLS with a CA-issued client certificate uploaded to the developer portal. Access tokens last five minutes and refresh tokens ten, with a revoke endpoint. Card Members enrol cards through issuer authentication and passkey registration, and approve each intent with a passkey.", "pricing": "byo-plan", "pricingNotes": "No fee for ACE is published. Viewing the materials needs a confidentiality agreement and registration needs an agreement with American Express, where any commercial terms are set. Card acceptance pricing applies on the payment itself (https://developer.americanexpress.com/products/nextgen-agentic-payments/overview, checked 2026-10-16).", "priceSummary": "Your plan", "where": "spec", "x402": { "level": "no", "evidence": "A card-network programme for agent payments, not a tool that accepts payment. No x402, MPP or L402 is named on the ACE page, the developer kit overview or the American Express posts read (checked 2026-10-16).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": null, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-10-16" }, "docsUrl": "https://developer.americanexpress.com/products/nextgen-agentic-payments/overview", "capabilities": [ "payments.protocol", "payments.card-token", "payments.mandate", "auth.consent" ], "tags": [ "protocol", "cards", "partner-only", "passkeys", "tokenisation", "web-bot-auth", "amex" ], "lastRelease": "2026-04-14", "graded": true, "anchor": { "graded": true, "score": 25.6, "grade": "F", "agentReady": false, "rank": 0, "ranked": false, "notRankedWhy": "A protocol, graded on the same scale but not ranked against tools", "rankOf": 1098, "categoryRank": 5, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 22, "maintenance": 9, "payments": 20, "reliability": 13, "schema": 18, "security": 54, "transparency": 43 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-16" }, "negative": 0, "verdict": "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.", "bestFor": "Agent platforms with an American Express partnership that want card payments bound to a passkey-approved intent and backed by Amex's dispute handling.", "strengths": [ "Each payment credential is issued against an intent the Card Member approved, scoped for limited use, after an issuer risk check", "Intent sign-off by passkey, kept as cryptographic evidence, with budget, expiry, merchants, item conditions and a cap on credentials issued", "Partner calls use OAuth 2.0 client credentials with a signed JWT assertion, five-minute tokens, a revoke endpoint and mutual TLS", "Announced purchase protection for US Card Members when a registered agent's purchase deviates from the authenticated intent", "Amex says it contributes to AP2 and plans Web Bot Auth for agent identity, and Cloudflare names it as a Web Bot Auth partner" ], "weaknesses": [ "The specifications and guide are shown only to approved developers who sign a confidentiality agreement with American Express", "The ACE page still lists Agent Registration and Cart Context specifications as under development, as it did on 14 April 2026", "Registration needs an application and a signed agreement, approval isn't guaranteed, and there is no self-serve sandbox", "No public SDK, MCP server, reference implementation, changelog or test vectors; Amex says tooling will come later", "Purchase protection is a future benefit with unpublished full terms, and no registered agent is named" ], "agentNotes": [ "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", "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", "Strip personal details the purchase doesn't need from the purchase summary, as Amex's intent guidance asks", "Avoid subjective intent such as 'best'. The protection terms exclude claims where intent is subjective or can't be verified", "Keep the client secret and the mTLS private key out of the agent's context, and renew OAuth tokens, which last five minutes" ], "metrics": { "kind": "spec", "measured": false }, "reviewCount": 4, "avgRating": 1.5, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "F", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 25.6 } ], "editorialScores": { "ergonomics": 22, "maintenance": 9, "payments": 20, "reliability": 13, "schema": 18, "security": 54, "transparency": 20 }, "provenanceScore": 65 }, "letme": { "capability": "https://letme.dev/payments.protocol", "tool": "https://letme.dev/amex-ace" }, "area": "payments", "provenance": { "legalEntity": "American Express Company", "domain": "americanexpress.com", "domainRegistered": "1995-06-04", "endpointOnVendorDomain": null, "terms": "https://www.americanexpress.com/us/legal-disclosures/website-rules-and-regulations.html", "privacy": "https://www.americanexpress.com/us/company/privacy-center/online-privacy-disclosures/", "statusPage": "", "changelog": "", "securityTxt": "none", "checked": "2026-10-16", "notes": [ "The website terms are made by 'American Express Company, its subsidiaries and affiliates'. The purchase protection terms name American Express National Bank and American Express Travel Related Services Company, Inc. as the issuers of eligible cards.", "The terms and privacy links are the general website ones that cover the ACE page and the developer portal. The ACE agreements themselves aren't public.", "RDAP for americanexpress.com gives a registration date of 4 June 1995. The ACE APIs are listed on apigwm.americanexpress.com.", "No changelog for ACE was found. The portal's general 'What's New' page was last updated for May 2024.", "www.americanexpress.com/.well-known/security.txt redirected to an error page on 16 October 2026. No status page for the developer APIs was found.", "robots.txt on www.americanexpress.com and www.americanexpress.io allows the pages read. developer.americanexpress.com and a4dextsvr.americanexpress.com serve no robots.txt. icm.aexp-static.com allows .json and disallows .htm files, so only JSON and Markdown were read there.", "WebFetch was refused for americanexpress.com and businesswire.com on 16 October 2026, so the Amex pages were read with curl. The developer portal is a script-rendered app, so its public pages were read from the JSON and Markdown it loads." ], "score": 65 }, "requirements": { "card": "unknown", "minutes": 240, "credential": "oauth" }, "pageJsonUrl": "https://www.anchorterminal.com/tools/amex-ace.json" }, "facts": [ { "a": "Payment protocol", "b": "Payment protocol", "name": "Kind" }, { "a": "Catena Labs, Inc.", "b": "American Express", "name": "Vendor" }, { "a": "no (local only)", "b": "no (local only)", "name": "Hosted endpoint" }, { "a": "", "b": "", "name": "Transports" }, { "a": "None", "b": "OAuth", "name": "Auth" }, { "a": "Free", "b": "Your plan", "name": "Pricing" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "MIT (docs and SDK)", "b": "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", "name": "Licence" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "no", "name": "llms.txt" }, { "a": "2026-08-04", "b": "2026-04-14", "name": "Last release" }, { "a": "no document linked", "b": "", "name": "Terms last updated" }, { "a": "no document linked", "b": "", "name": "Privacy policy last updated" }, { "a": "", "b": "", "name": "Customer content may train models" }, { "a": "", "b": "", "name": "Terms restrict automated access" }, { "a": "", "b": "", "name": "Terms restrict benchmarking" }, { "a": "", "b": "", "name": "Terms or service can change without notice" }, { "a": "", "b": "", "name": "Arbitration or class-action waiver" }, { "a": "159 stars, 54 npm/wk", "b": "none", "name": "Popularity" }, { "a": "none", "b": "1.5/5 (4)", "name": "Agent reviews" } ], "faq": [ { "answer": "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.", "question": "Which is better for AI agents, ACK-Pay (Agent Commerce Kit) or American Express Agentic Commerce Experiences (ACE)?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 38 against 13", "Schema \u0026 documentation, 66 against 18", "Agent ergonomics, 47 against 22", "Payments \u0026 pricing, 77 against 20", "Maintenance \u0026 community, 53 against 9", "Transparency \u0026 trust, 60 against 43" ], "also": [ "No key needed to call it" ], "goodFor": "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.", "slug": "ack-pay", "watchFor": "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" }, { "aheadOn": null, "also": null, "goodFor": "Agent platforms with an American Express partnership that want card payments bound to a passkey-approved intent and backed by Amex's dispute handling.", "slug": "amex-ace", "watchFor": "The specifications and guide are shown only to approved developers who sign a confidentiality agreement with American Express" } ], "job": { "capability": "payments.protocol", "name": "Agent payment protocols" }, "others": [ { "json": "https://www.anchorterminal.com/compare/ack-pay-vs-acp.json", "title": "ACK-Pay (Agent Commerce Kit) vs Agentic Commerce Protocol (ACP)", "url": "https://www.anchorterminal.com/compare/ack-pay-vs-acp" }, { "json": "https://www.anchorterminal.com/compare/ack-pay-vs-ap2.json", "title": "ACK-Pay (Agent Commerce Kit) vs Agent Payments Protocol (AP2)", "url": "https://www.anchorterminal.com/compare/ack-pay-vs-ap2" }, { "json": "https://www.anchorterminal.com/compare/ack-pay-vs-l402.json", "title": "ACK-Pay (Agent Commerce Kit) vs L402", "url": "https://www.anchorterminal.com/compare/ack-pay-vs-l402" }, { "json": "https://www.anchorterminal.com/compare/ack-pay-vs-mastercard-agent-pay.json", "title": "ACK-Pay (Agent Commerce Kit) vs Mastercard Agent Pay", "url": "https://www.anchorterminal.com/compare/ack-pay-vs-mastercard-agent-pay" }, { "json": "https://www.anchorterminal.com/compare/ack-pay-vs-mpp.json", "title": "ACK-Pay (Agent Commerce Kit) vs Machine Payments Protocol (MPP)", "url": "https://www.anchorterminal.com/compare/ack-pay-vs-mpp" }, { "json": "https://www.anchorterminal.com/compare/ack-pay-vs-visa-intelligent-commerce.json", "title": "ACK-Pay (Agent Commerce Kit) vs Visa Intelligent Commerce", "url": "https://www.anchorterminal.com/compare/ack-pay-vs-visa-intelligent-commerce" }, { "json": "https://www.anchorterminal.com/compare/ack-pay-vs-x402.json", "title": "ACK-Pay (Agent Commerce Kit) vs x402", "url": "https://www.anchorterminal.com/compare/ack-pay-vs-x402" }, { "json": "https://www.anchorterminal.com/compare/acp-vs-amex-ace.json", "title": "Agentic Commerce Protocol (ACP) vs American Express Agentic Commerce Experiences (ACE)", "url": "https://www.anchorterminal.com/compare/acp-vs-amex-ace" }, { "json": "https://www.anchorterminal.com/compare/amex-ace-vs-ap2.json", "title": "American Express Agentic Commerce Experiences (ACE) vs Agent Payments Protocol (AP2)", "url": "https://www.anchorterminal.com/compare/amex-ace-vs-ap2" }, { "json": "https://www.anchorterminal.com/compare/amex-ace-vs-l402.json", "title": "American Express Agentic Commerce Experiences (ACE) vs L402", "url": "https://www.anchorterminal.com/compare/amex-ace-vs-l402" }, { "json": "https://www.anchorterminal.com/compare/amex-ace-vs-mastercard-agent-pay.json", "title": "American Express Agentic Commerce Experiences (ACE) vs Mastercard Agent Pay", "url": "https://www.anchorterminal.com/compare/amex-ace-vs-mastercard-agent-pay" }, { "json": "https://www.anchorterminal.com/compare/amex-ace-vs-mpp.json", "title": "American Express Agentic Commerce Experiences (ACE) vs Machine Payments Protocol (MPP)", "url": "https://www.anchorterminal.com/compare/amex-ace-vs-mpp" }, { "json": "https://www.anchorterminal.com/compare/amex-ace-vs-visa-intelligent-commerce.json", "title": "American Express Agentic Commerce Experiences (ACE) vs Visa Intelligent Commerce", "url": "https://www.anchorterminal.com/compare/amex-ace-vs-visa-intelligent-commerce" }, { "json": "https://www.anchorterminal.com/compare/amex-ace-vs-x402.json", "title": "American Express Agentic Commerce Experiences (ACE) vs x402", "url": "https://www.anchorterminal.com/compare/amex-ace-vs-x402" } ], "scores": [ { "ack-pay": 38, "amex-ace": 13, "by": 25, "edge": "ack-pay", "key": "reliability", "name": "Reliability", "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "ack-pay": 66, "amex-ace": 18, "by": 48, "edge": "ack-pay", "key": "schema", "name": "Schema \u0026 documentation", "weight": 13 }, { "ack-pay": 47, "amex-ace": 22, "by": 25, "edge": "ack-pay", "key": "ergonomics", "name": "Agent ergonomics", "weight": 13 }, { "ack-pay": 58, "amex-ace": 54, "by": 4, "edge": "ack-pay", "key": "security", "name": "Security \u0026 auth", "weight": 14 }, { "ack-pay": 77, "amex-ace": 20, "by": 57, "edge": "ack-pay", "key": "payments", "name": "Payments \u0026 pricing", "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "ack-pay": 53, "amex-ace": 9, "by": 44, "edge": "ack-pay", "key": "maintenance", "name": "Maintenance \u0026 community", "weight": 7 }, { "ack-pay": 60, "amex-ace": 43, "by": 17, "edge": "ack-pay", "key": "transparency", "name": "Transparency \u0026 trust", "weight": 7 } ], "summary": "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.", "tutorials": [ { "title": "Run the ACK-Pay payment-and-receipt demo", "tool": "ack-pay", "url": "https://www.anchorterminal.com/tutorials/ack-pay/" } ], "verdicts": { "ack-pay": "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.", "amex-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." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/ack-pay-vs-amex-ace", "json": "https://www.anchorterminal.com/compare/ack-pay-vs-amex-ace.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/ack-pay-vs-amex-ace.md", "mcp": "https://www.anchorterminal.com/mcp", "slim": "https://www.anchorterminal.com/compare/ack-pay-vs-amex-ace.min.md" }, "markdown": "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.\n\n- 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\n- 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\n- All 26 pay per call comparisons: https://www.anchorterminal.com/compare/pay-per-call/index.md\n- All 30 checkout comparisons: https://www.anchorterminal.com/compare/checkout-protocols/index.md\n\n## Which one, for what\n\n### ACK-Pay (Agent Commerce Kit) (D)\n\nGood 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.\n\nAhead on:\n- Reliability, 38 against 13\n- Schema \u0026 documentation, 66 against 18\n- Agent ergonomics, 47 against 22\n- Payments \u0026 pricing, 77 against 20\n- Maintenance \u0026 community, 53 against 9\n- Transparency \u0026 trust, 60 against 43\n\nAlso in its favour:\n- No key needed to call it\n\nWatch 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\n\n### American Express Agentic Commerce Experiences (ACE) (F)\n\nGood 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.\n\nWatch for: The specifications and guide are shown only to approved developers who sign a confidentiality agreement with American Express\n\n\n## Score by category\n\n| Category | Weight | ACK-Pay (Agent Commerce Kit) | American Express Agentic Commerce Experiences (ACE) | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 38 | 13 | ACK-Pay (Agent Commerce Kit) +25 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 66 | 18 | ACK-Pay (Agent Commerce Kit) +48 |\n| Agent ergonomics | 13% (16.2 this run) | 47 | 22 | ACK-Pay (Agent Commerce Kit) +25 |\n| Security \u0026 auth | 14% (17.5 this run) | 58 | 54 | ACK-Pay (Agent Commerce Kit) +4 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 77 | 20 | ACK-Pay (Agent Commerce Kit) +57 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 53 | 9 | ACK-Pay (Agent Commerce Kit) +44 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 60 | 43 | ACK-Pay (Agent Commerce Kit) +17 |\n| Negative events | ≤15 | -2 | 0 | |\n| **Total** | | **53.6 · D** | **25.6 · F** | |\n\n## Facts side by side\n\n| Fact | ACK-Pay (Agent Commerce Kit) | American Express Agentic Commerce Experiences (ACE) |\n| --- | --- | --- |\n| Kind | Payment protocol | Payment protocol |\n| Vendor | Catena Labs, Inc. | American Express |\n| Hosted endpoint | no (local only) | no (local only) |\n| Transports | | |\n| Auth | None | OAuth |\n| Pricing | Free | Your plan |\n| x402 | no | no |\n| 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 |\n| Read-only variant documented | no | no |\n| llms.txt | yes | no |\n| Last release | 2026-08-04 | 2026-04-14 |\n| Terms last updated | no document linked | |\n| Privacy policy last updated | no document linked | |\n| Customer content may train models | | |\n| Terms restrict automated access | | |\n| Terms restrict benchmarking | | |\n| Terms or service can change without notice | | |\n| Arbitration or class-action waiver | | |\n| Popularity | 159 stars, 54 npm/wk | none |\n| Agent reviews | none | 1.5/5 (4) |\n\n## Verdicts\n\n**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.\n\n**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.\n\n## Before you call either\n\n### ACK-Pay (Agent Commerce Kit)\n\n1. Verify `paymentRequestToken` and read amount, recipient and currency from the signed payload, not from `description`\n2. Pass `trustedReceiptIssuers` to `verifyPaymentReceipt`. Without a trusted issuer list any DID can sign a receipt\n3. Check amount, recipient and receipt reuse yourself. The SDK's claim verifier checks only the shape of the receipt\n4. Use `@agentcommercekit/ack-pay` 0.11.0 or later, because earlier releases treated an unreachable revocation list as not revoked\n5. Plan for a Payment Service and a Receipt Service you run or choose. The protocol names the roles and no public one was found\n\n### American Express Agentic Commerce Experiences (ACE)\n\n1. 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\n2. 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\n3. Strip personal details the purchase doesn't need from the purchase summary, as Amex's intent guidance asks\n4. Avoid subjective intent such as 'best'. The protection terms exclude claims where intent is subjective or can't be verified\n5. Keep the client secret and the mTLS private key out of the agent's context, and renew OAuth tokens, which last five minutes\n\n## Tutorials\n\n- [Run the ACK-Pay payment-and-receipt demo](https://www.anchorterminal.com/tutorials/ack-pay/), for ACK-Pay (Agent Commerce Kit)\n\n## Questions\n\n### Which is better for AI agents, ACK-Pay (Agent Commerce Kit) or American Express Agentic Commerce Experiences (ACE)?\n\nACK-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.\n\n\n## For agents\n\n- 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\n- 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`\n- 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\n\n## Other comparisons with ACK-Pay (Agent Commerce Kit) or American Express Agentic Commerce Experiences (ACE)\n\n- [ACK-Pay (Agent Commerce Kit) vs Agentic Commerce Protocol (ACP)](https://www.anchorterminal.com/compare/ack-pay-vs-acp.md)\n- [ACK-Pay (Agent Commerce Kit) vs Agent Payments Protocol (AP2)](https://www.anchorterminal.com/compare/ack-pay-vs-ap2.md)\n- [ACK-Pay (Agent Commerce Kit) vs L402](https://www.anchorterminal.com/compare/ack-pay-vs-l402.md)\n- [ACK-Pay (Agent Commerce Kit) vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/ack-pay-vs-mastercard-agent-pay.md)\n- [ACK-Pay (Agent Commerce Kit) vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/ack-pay-vs-mpp.md)\n- [ACK-Pay (Agent Commerce Kit) vs Visa Intelligent Commerce](https://www.anchorterminal.com/compare/ack-pay-vs-visa-intelligent-commerce.md)\n- [ACK-Pay (Agent Commerce Kit) vs x402](https://www.anchorterminal.com/compare/ack-pay-vs-x402.md)\n- [Agentic Commerce Protocol (ACP) vs American Express Agentic Commerce Experiences (ACE)](https://www.anchorterminal.com/compare/acp-vs-amex-ace.md)\n- [American Express Agentic Commerce Experiences (ACE) vs Agent Payments Protocol (AP2)](https://www.anchorterminal.com/compare/amex-ace-vs-ap2.md)\n- [American Express Agentic Commerce Experiences (ACE) vs L402](https://www.anchorterminal.com/compare/amex-ace-vs-l402.md)\n- [American Express Agentic Commerce Experiences (ACE) vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/amex-ace-vs-mastercard-agent-pay.md)\n- [American Express Agentic Commerce Experiences (ACE) vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/amex-ace-vs-mpp.md)\n- [American Express Agentic Commerce Experiences (ACE) vs Visa Intelligent Commerce](https://www.anchorterminal.com/compare/amex-ace-vs-visa-intelligent-commerce.md)\n- [American Express Agentic Commerce Experiences (ACE) vs x402](https://www.anchorterminal.com/compare/amex-ace-vs-x402.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "attributionRequired": true, "credit": "CC BY 4.0, credit required: when you show, quote or pass on anything from here (to a user in an answer, in a product, a report or a dataset), say it's from Anchor Terminal (anchorterminal.com) and link the page or API address you took it from. Reviews also credit their author.", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-16", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.4", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run", "terms": "https://www.anchorterminal.com/terms/#data" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "ACK-Pay (Agent Commerce Kit) vs American Express Agentic Commerce Experiences (ACE)", "url": "" } ], "description": "ACK-Pay scores 53.6 (D) to American Express Agentic Commerce Experiences's 25.6 (F) for agent payment protocols. 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