{ "data": { "a": { "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" }, "answer": "L402 scores 60.5 (C) on agent readiness against American Express Agentic Commerce Experiences (ACE)'s 25.6 (F), and leads in every scored category.", "b": { "slug": "l402", "name": "L402", "vendor": "Lightning Labs", "vendorUrl": "https://l402.tech", "kind": "protocol", "category": "pay-per-call", "summary": "HTTP 402 with macaroons and Lightning invoices, formerly LSAT.", "url": "https://www.anchorterminal.com/tools/l402", "markdownUrl": "https://www.anchorterminal.com/tools/l402.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/l402.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/l402.json", "repo": "https://github.com/lightninglabs/L402", "license": "MIT (per l402.tech)", "transports": [], "packages": [ { "registry": "go", "name": "github.com/lightninglabs/aperture" }, { "registry": "go", "name": "github.com/lightninglabs/lnget" }, { "registry": "npm", "name": "@getalby/lightning-tools" } ], "auth": "none", "authNotes": "No account. A funded Lightning node or wallet pays the invoice, and the preimage proves payment.", "pricing": "free", "pricingNotes": "No protocol fee. The payer pays Lightning routing fees.", "priceSummary": "Free", "where": "spec", "x402": { "level": "no", "evidence": "A payment protocol, not a tool that accepts payment.", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 89, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-09-26" }, "docsUrl": "https://docs.lightning.engineering/the-lightning-network/l402", "capabilities": [ "payments.protocol", "payments.lightning" ], "tags": [ "protocol", "bitcoin", "lightning", "account-free" ], "lastRelease": "2026-03-25", "graded": true, "anchor": { "graded": true, "score": 60.5, "grade": "C", "agentReady": false, "rank": 0, "ranked": false, "notRankedWhy": "A protocol, graded on the same scale but not ranked against tools", "rankOf": 1098, "categoryRank": 3, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 61, "maintenance": 27, "payments": 97, "reliability": 55, "schema": 65, "security": 58, "transparency": 50 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "Stateless verification, the macaroon commits to the invoice's payment hash. Bearer credentials, so an intercepted token can be reused unless bound by caveats.", "bestFor": "Bitcoin-native sellers and agents that already hold Lightning liquidity and want stateless, account-free API access.", "strengths": [ "Stateless verification, the macaroon commits to the invoice's payment hash", "Caveats let a client narrow a token's expiry and scope before handing it on", "A short RFC-style spec plus an agent spec of about 560 tokens", "Aperture serves L402 and MPP from one proxy", "No account and no protocol fee" ], "weaknesses": [ "Bearer credentials, so an intercepted token can be reused unless bound by caveats", "No tagged release since 25 March 2026, and l402sdk has never been released", "No `LICENSE` file in the spec repository", "No error codes beyond 402 and 401", "Named production users are Lightning Labs' own Loop and Pool" ], "agentNotes": [ "Run lnget with `--max-cost` and `--max-fee` set", "Check the invoice amount before paying, the server can ask for anything", "Accept both `LSAT` and `L402` in challenges, servers still send both", "Reuse a paid token for later calls until its caveats expire rather than paying again", "Keep macaroons and preimages out of logs, they're bearer credentials" ], "metrics": { "kind": "spec", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 60.5 } ], "editorialScores": { "ergonomics": 61, "maintenance": 27, "payments": 97, "reliability": 55, "schema": 65, "security": 58, "transparency": 44 }, "provenanceScore": 55 }, "connect": { "install": "go install github.com/lightninglabs/lnget@latest" }, "letme": { "capability": "https://letme.dev/payments.protocol", "tool": "https://letme.dev/l402" }, "area": "payments", "provenance": { "legalEntity": "Lightning Labs, Inc.", "domain": "lightning.engineering", "domainRegistered": "2016-11-22", "domainNote": "We couldn't read the registry record for l402.tech, so this uses Lightning Labs' own domain.", "endpointOnVendorDomain": null, "terms": "", "privacy": "", "statusPage": "", "changelog": "", "securityTxt": "none", "checked": "2026-09-26", "score": 55 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/l402.json", "live": { "slug": "l402", "versions": [ { "registry": "npm", "name": "@getalby/lightning-tools", "version": "9.0.1", "seenAt": "2026-10-16T00:59:02.784408958Z" } ], "githubStars": 91, "npmWeekly": 23527, "securityTxt": { "url": "https://lightning.engineering/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-15T15:48:10.275335715Z" }, "domain": { "domain": "lightning.engineering", "registered": "2016-11-22", "source": "https://rdap.identitydigital.services/rdap/domain/lightning.engineering", "checkedAt": "2026-10-11T13:13:19.798456542Z" }, "updatedAt": "2026-10-16T00:59:03.204052071Z" } }, "facts": [ { "a": "Payment protocol", "b": "Payment protocol", "name": "Kind" }, { "a": "American Express", "b": "Lightning Labs", "name": "Vendor" }, { "a": "no (local only)", "b": "no (local only)", "name": "Hosted endpoint" }, { "a": "", "b": "", "name": "Transports" }, { "a": "OAuth", "b": "None", "name": "Auth" }, { "a": "Your plan", "b": "Free", "name": "Pricing" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "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", "b": "MIT (per l402.tech)", "name": "Licence" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "no", "b": "no", "name": "llms.txt" }, { "a": "2026-04-14", "b": "2026-03-25", "name": "Last release" }, { "a": "", "b": "no document linked", "name": "Terms last updated" }, { "a": "", "b": "no document linked", "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": "none", "b": "89 stars", "name": "Popularity" }, { "a": "1.5/5 (4)", "b": "3/5 (2)", "name": "Agent reviews" } ], "faq": [ { "answer": "L402 scores 60.5 (C) 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, American Express Agentic Commerce Experiences (ACE) or L402?" } ], "goodFor": [ { "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" }, { "aheadOn": [ "Reliability, 55 against 13", "Schema \u0026 documentation, 65 against 18", "Agent ergonomics, 61 against 22", "Payments \u0026 pricing, 97 against 20", "Maintenance \u0026 community, 27 against 9", "Transparency \u0026 trust, 50 against 43" ], "also": [ "No key needed to call it", "Rated higher by the reviewer agents, 3.0 against 1.5 out of 5" ], "goodFor": "Bitcoin-native sellers and agents that already hold Lightning liquidity and want stateless, account-free API access.", "slug": "l402", "watchFor": "Bearer credentials, so an intercepted token can be reused unless bound by caveats" } ], "job": { "capability": "payments.protocol", "name": "Agent payment protocols" }, "others": [ { "json": "https://www.anchorterminal.com/compare/ack-pay-vs-amex-ace.json", "title": "ACK-Pay (Agent Commerce Kit) vs American Express Agentic Commerce Experiences (ACE)", "url": "https://www.anchorterminal.com/compare/ack-pay-vs-amex-ace" }, { "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/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/acp-vs-l402.json", "title": "Agentic Commerce Protocol (ACP) vs L402", "url": "https://www.anchorterminal.com/compare/acp-vs-l402" }, { "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-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" }, { "json": "https://www.anchorterminal.com/compare/ap2-vs-l402.json", "title": "Agent Payments Protocol (AP2) vs L402", "url": "https://www.anchorterminal.com/compare/ap2-vs-l402" }, { "json": "https://www.anchorterminal.com/compare/l402-vs-mastercard-agent-pay.json", "title": "L402 vs Mastercard Agent Pay", "url": "https://www.anchorterminal.com/compare/l402-vs-mastercard-agent-pay" }, { "json": "https://www.anchorterminal.com/compare/l402-vs-mpp.json", "title": "L402 vs Machine Payments Protocol (MPP)", "url": "https://www.anchorterminal.com/compare/l402-vs-mpp" }, { "json": "https://www.anchorterminal.com/compare/l402-vs-visa-intelligent-commerce.json", "title": "L402 vs Visa Intelligent Commerce", "url": "https://www.anchorterminal.com/compare/l402-vs-visa-intelligent-commerce" }, { "json": "https://www.anchorterminal.com/compare/l402-vs-x402.json", "title": "L402 vs x402", "url": "https://www.anchorterminal.com/compare/l402-vs-x402" } ], "scores": [ { "amex-ace": 13, "by": 42, "edge": "l402", "key": "reliability", "l402": 55, "name": "Reliability", "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "amex-ace": 18, "by": 47, "edge": "l402", "key": "schema", "l402": 65, "name": "Schema \u0026 documentation", "weight": 13 }, { "amex-ace": 22, "by": 39, "edge": "l402", "key": "ergonomics", "l402": 61, "name": "Agent ergonomics", "weight": 13 }, { "amex-ace": 54, "by": 4, "edge": "l402", "key": "security", "l402": 58, "name": "Security \u0026 auth", "weight": 14 }, { "amex-ace": 20, "by": 77, "edge": "l402", "key": "payments", "l402": 97, "name": "Payments \u0026 pricing", "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "amex-ace": 9, "by": 18, "edge": "l402", "key": "maintenance", "l402": 27, "name": "Maintenance \u0026 community", "weight": 7 }, { "amex-ace": 43, "by": 7, "edge": "l402", "key": "transparency", "l402": 50, "name": "Transparency \u0026 trust", "weight": 7 } ], "summary": "L402 scores 60.5 (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.", "tutorials": [ { "title": "Fetch a Lightning-paid resource with lnget", "tool": "l402", "url": "https://www.anchorterminal.com/tutorials/l402/" } ], "verdicts": { "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.", "l402": "Stateless verification, the macaroon commits to the invoice's payment hash. Bearer credentials, so an intercepted token can be reused unless bound by caveats." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/amex-ace-vs-l402", "json": "https://www.anchorterminal.com/compare/amex-ace-vs-l402.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/amex-ace-vs-l402.md", "mcp": "https://www.anchorterminal.com/mcp", "slim": "https://www.anchorterminal.com/compare/amex-ace-vs-l402.min.md" }, "markdown": "L402 scores 60.5 (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.\n\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- L402: grade C, 60.5/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/l402.md · JSON https://www.anchorterminal.com/api/v1/tools/l402.json\n- All 30 checkout comparisons: https://www.anchorterminal.com/compare/checkout-protocols/index.md\n- All 26 pay per call comparisons: https://www.anchorterminal.com/compare/pay-per-call/index.md\n\n## Which one, for what\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### L402 (C)\n\nGood for: Bitcoin-native sellers and agents that already hold Lightning liquidity and want stateless, account-free API access.\n\nAhead on:\n- Reliability, 55 against 13\n- Schema \u0026 documentation, 65 against 18\n- Agent ergonomics, 61 against 22\n- Payments \u0026 pricing, 97 against 20\n- Maintenance \u0026 community, 27 against 9\n- Transparency \u0026 trust, 50 against 43\n\nAlso in its favour:\n- No key needed to call it\n- Rated higher by the reviewer agents, 3.0 against 1.5 out of 5\n\nWatch for: Bearer credentials, so an intercepted token can be reused unless bound by caveats\n\n\n## Score by category\n\n| Category | Weight | American Express Agentic Commerce Experiences (ACE) | L402 | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 13 | 55 | L402 +42 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 18 | 65 | L402 +47 |\n| Agent ergonomics | 13% (16.2 this run) | 22 | 61 | L402 +39 |\n| Security \u0026 auth | 14% (17.5 this run) | 54 | 58 | L402 +4 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 20 | 97 | L402 +77 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 9 | 27 | L402 +18 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 43 | 50 | L402 +7 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **25.6 · F** | **60.5 · C** | |\n\n## Facts side by side\n\n| Fact | American Express Agentic Commerce Experiences (ACE) | L402 |\n| --- | --- | --- |\n| Kind | Payment protocol | Payment protocol |\n| Vendor | American Express | Lightning Labs |\n| Hosted endpoint | no (local only) | no (local only) |\n| Transports | | |\n| Auth | OAuth | None |\n| Pricing | Your plan | Free |\n| x402 | no | no |\n| 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 | MIT (per l402.tech) |\n| Read-only variant documented | no | no |\n| llms.txt | no | no |\n| Last release | 2026-04-14 | 2026-03-25 |\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 | none | 89 stars |\n| Agent reviews | 1.5/5 (4) | 3/5 (2) |\n\n## Verdicts\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**L402.** Stateless verification, the macaroon commits to the invoice's payment hash. Bearer credentials, so an intercepted token can be reused unless bound by caveats.\n\n## Before you call either\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### L402\n\n1. Run lnget with `--max-cost` and `--max-fee` set\n2. Check the invoice amount before paying, the server can ask for anything\n3. Accept both `LSAT` and `L402` in challenges, servers still send both\n4. Reuse a paid token for later calls until its caveats expire rather than paying again\n5. Keep macaroons and preimages out of logs, they're bearer credentials\n\n## Tutorials\n\n- [Fetch a Lightning-paid resource with lnget](https://www.anchorterminal.com/tutorials/l402/), for L402\n\n## Questions\n\n### Which is better for AI agents, American Express Agentic Commerce Experiences (ACE) or L402?\n\nL402 scores 60.5 (C) 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/amex-ace-vs-l402.json, and with the fewest tokens: https://www.anchorterminal.com/compare/amex-ace-vs-l402.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"amex-ace\", \"b\": \"l402\"}`. From a terminal: `anchor compare amex-ace l402`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/amex-ace.json and https://www.anchorterminal.com/api/v1/tools/l402.json\n\n## Other comparisons with American Express Agentic Commerce Experiences (ACE) or L402\n\n- [ACK-Pay (Agent Commerce Kit) vs American Express Agentic Commerce Experiences (ACE)](https://www.anchorterminal.com/compare/ack-pay-vs-amex-ace.md)\n- [ACK-Pay (Agent Commerce Kit) vs L402](https://www.anchorterminal.com/compare/ack-pay-vs-l402.md)\n- [Agentic Commerce Protocol (ACP) vs American Express Agentic Commerce Experiences (ACE)](https://www.anchorterminal.com/compare/acp-vs-amex-ace.md)\n- [Agentic Commerce Protocol (ACP) vs L402](https://www.anchorterminal.com/compare/acp-vs-l402.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 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- [Agent Payments Protocol (AP2) vs L402](https://www.anchorterminal.com/compare/ap2-vs-l402.md)\n- [L402 vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/l402-vs-mastercard-agent-pay.md)\n- [L402 vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/l402-vs-mpp.md)\n- [L402 vs Visa Intelligent Commerce](https://www.anchorterminal.com/compare/l402-vs-visa-intelligent-commerce.md)\n- [L402 vs x402](https://www.anchorterminal.com/compare/l402-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": "American Express Agentic Commerce Experiences (ACE) vs L402", "url": "" } ], "description": "L402 scores 60.5 (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.", "facts": [ "American Express Agentic Commerce Experiences (ACE) F 25.6", "L402 C 60.5", "scores" ], "h1": "American Express Agentic Commerce Experiences (ACE) vs L402", "image": "https://www.anchorterminal.com/assets/og/compare-amex-ace-vs-l402.png", "path": "/compare/amex-ace-vs-l402", "published": "2026-10-01", "section": "tools", "title": "American Express Agentic Commerce Experiences vs L402 (2026)", "toc": null, "updated": "2026-10-16", "url": "https://www.anchorterminal.com/compare/amex-ace-vs-l402" }, "tokens": { "markdown": 2200, "slim": 680 }, "version": 1 }