{ "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": 950, "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": "2026-10-09T16:36:08.43967526Z" }, { "registry": "npm", "name": "@agentcommercekit/ack-pay", "version": "0.11.0", "seenAt": "2026-10-09T16:36:05.977895912Z" }, { "registry": "npm", "name": "agentcommercekit", "version": "0.11.0", "seenAt": "2026-10-09T16:36:06.897286657Z" } ], "githubStars": 159, "npmWeekly": 54, "pages": [ { "url": "https://raw.githubusercontent.com/agentcommercekit/ack/main/packages/ack-pay/CHANGELOG.md", "kind": "changelog", "status": 200, "checkedAt": "2026-10-09T18:44:49.200254285Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "a86c2ee19456" } ], "updatedAt": "2026-10-09T18:44:49.200254285Z" } }, "answer": "x402 scores 79.7 (A) on agent readiness against ACK-Pay (Agent Commerce Kit)'s 53.6 (D), and leads in every scored category.", "b": { "slug": "x402", "name": "x402", "vendor": "x402 Foundation (Linux Foundation)", "vendorUrl": "https://x402.org", "kind": "protocol", "category": "pay-per-call", "summary": "Protocol for per-request stablecoin payments using HTTP 402.", "url": "https://www.anchorterminal.com/tools/x402", "markdownUrl": "https://www.anchorterminal.com/tools/x402.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/x402.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/x402.json", "repo": "https://github.com/x402-foundation/x402", "license": "Apache-2.0", "transports": [], "packages": [ { "registry": "npm", "name": "@x402/core" }, { "registry": "npm", "name": "@x402/fetch" }, { "registry": "pypi", "name": "x402" }, { "registry": "go", "name": "github.com/x402-foundation/x402/go" } ], "auth": "none", "authNotes": "No account. A funded wallet signs each payment. Facilitators may screen addresses (Coinbase CDP runs OFAC and KYT checks).", "pricing": "free", "pricingNotes": "No protocol fee. The Coinbase CDP facilitator settles 1,000 transactions a month free, then $0.001 each, and pays gas in the exact scheme. Stripe charges 1.5% for x402 with gas included (https://docs.cdp.coinbase.com/x402/core-concepts/facilitator).", "priceSummary": "Free · OSS", "where": "spec", "x402": { "level": "no", "evidence": "A payment protocol, not a tool that accepts payment.", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 6400, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-10-01" }, "docsUrl": "https://docs.x402.org", "llmsTxt": "https://docs.x402.org/llms.txt", "capabilities": [ "payments.protocol", "payments.x402", "payments.stablecoin" ], "tags": [ "protocol", "open-source", "stablecoin", "account-free", "foundation" ], "lastRelease": "2026-09-30", "graded": true, "anchor": { "graded": true, "score": 79.7, "grade": "A", "agentReady": true, "rank": 0, "ranked": false, "notRankedWhy": "A protocol, graded on the same scale but not ranked against tools", "rankOf": 950, "categoryRank": 2, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 84, "maintenance": 93, "payments": 97, "reliability": 87, "schema": 86, "security": 67, "transparency": 65 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "high", "date": "2026-10-01" }, "negative": -3, "negativeNotes": [ "2026-03-06, GHSA-qr2g-p6q7-w82m (high). Facilitators processing Solana payments on @x402/svm before 2.6.0, Python x402 before 2.3.0 or Go before 2.5.0 were exposed. Keys and funds weren't affected, and the fix and advisory were public, so we deduct 2 (https://github.com/x402-foundation/x402/security/advisories/GHSA-qr2g-p6q7-w82m)", "2026-05-12, five attacks on x402 validated on local chains, Base Sepolia and live endpoints, across authorisation, binding, replay and web handling, causing unpaid service or paid-but-denied outcomes. Some related fixes appear in the repository (origin binding for sign-in, SSRF in Bazaar), but we couldn't confirm all five are closed, so we deduct 1 (https://arxiv.org/abs/2605.11781)" ], "verdict": "No account and no protocol fee, a funded wallet is enough. Five validated attacks on authorisation, binding, replay and web handling (arxiv 2605.11781).", "bestFor": "The default for an agent paying APIs per call in stablecoins without accounts, and the protocol most sellers in this directory speak.", "strengths": [ "No account and no protocol fee, a funded wallet is enough", "Reference SDKs in TypeScript, Python, Go and Java, released weekly", "15 public facilitators listed in the docs, several with no fees", "Exact, upto, auth-capture and batch-settlement schemes, with exact specs for 17 networks", "Standard error codes, including a non-terminal settlement_pending with the transaction hash" ], "weaknesses": [ "Five validated attacks on authorisation, binding, replay and web handling (arxiv 2605.11781)", "A high-severity facilitator advisory on Solana handling in March 2026", "Spend budgets sit outside the spec, only the upto scheme caps an amount", "The FAQ and the exact-scheme spec disagree on who pays gas", "Security reports still go to Coinbase's HackerOne rather than a foundation channel" ], "agentNotes": [ "Decode PAYMENT-REQUIRED and check amount, asset and payTo against what you expected before signing", "Use the upto scheme when the final price isn't known, and cap it", "On settlement_pending, look up the returned transaction hash before paying again", "Use a production facilitator for Base mainnet, x402.org/facilitator is testnet only", "Give the agent its own wallet with a small balance, never a treasury key" ], "metrics": { "kind": "spec", "measured": false }, "reviewCount": 2, "avgRating": 4.5, "history": [ { "basis": "public evidence", "confidence": "high", "grade": "A", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 79.7 } ], "editorialScores": { "ergonomics": 84, "maintenance": 93, "payments": 97, "reliability": 87, "schema": 86, "security": 67, "transparency": 72 }, "provenanceScore": 57 }, "connect": { "install": "npm i @x402/fetch # or: pip install x402", "http": "curl -i https://api.exa.ai/search -H \"content-type: application/json\" -d '{\"query\":\"x402\"}'\n# 402 Payment Required, PAYMENT-REQUIRED: \u003cbase64 JSON of accepted schemes\u003e\n# retry with PAYMENT-SIGNATURE: \u003cbase64 signed payment\u003e" }, "letme": { "capability": "https://letme.dev/payments.protocol", "tool": "https://letme.dev/x402" }, "area": "payments", "unitPrices": [ { "item": "CDP facilitator after 1,000 a month", "unit": "tx", "usd": 0.001 }, { "item": "Stripe x402 processing", "unit": "pct", "usd": 1.5, "note": "gas included" } ], "provenance": { "legalEntity": "x402, a Series of LF Projects, LLC", "domain": "x402.org", "domainRegistered": "2025-02-20", "endpointOnVendorDomain": null, "terms": "", "privacy": "", "statusPage": "", "changelog": "https://github.com/x402-foundation/x402/blob/main/typescript/packages/core/CHANGELOG.md", "securityTxt": "none", "checked": "2026-09-26", "score": 57 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/x402.json", "live": { "slug": "x402", "versions": [ { "registry": "npm", "name": "@x402/core", "version": "2.28.0", "seenAt": "2026-10-09T17:29:00.927195931Z" }, { "registry": "npm", "name": "@x402/fetch", "version": "2.28.0", "seenAt": "2026-10-09T17:29:01.968617333Z" }, { "registry": "pypi", "name": "x402", "version": "2.25.0", "released": "2026-09-29", "seenAt": "2026-10-09T17:29:03.142853448Z" } ], "githubStars": 6692, "npmWeekly": 344090, "pypiWeekly": 67152, "securityTxt": { "url": "https://x402.org/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-09T15:40:17.990897713Z" }, "llmsTxt": { "url": "https://docs.x402.org/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-09T14:03:01.99994064Z" }, "domain": { "domain": "x402.org", "registered": "2025-02-20", "source": "https://rdap.publicinterestregistry.org/rdap/domain/x402.org", "checkedAt": "2026-10-04T13:06:17.301998006Z" }, "pages": [ { "url": "https://raw.githubusercontent.com/x402-foundation/x402/main/typescript/packages/core/CHANGELOG.md", "kind": "changelog", "status": 304, "checkedAt": "2026-10-09T18:46:29.130826246Z", "changedAt": "2026-09-30T13:10:50.25107695Z", "fingerprint": "c6db0dd5efbf" }, { "url": "https://docs.x402.org/guides/migration-v1-to-v2.md", "kind": "deprecations", "status": 200, "checkedAt": "2026-10-09T18:38:48.407291606Z", "changedAt": "2026-10-02T15:20:40.840729903Z", "fingerprint": "c1eede7ddb9c" } ], "updatedAt": "2026-10-09T18:46:29.130826246Z" } }, "facts": [ { "a": "Payment protocol", "b": "Payment protocol", "name": "Kind" }, { "a": "Catena Labs, Inc.", "b": "x402 Foundation (Linux Foundation)", "name": "Vendor" }, { "a": "no (local only)", "b": "no (local only)", "name": "Hosted endpoint" }, { "a": "", "b": "", "name": "Transports" }, { "a": "None", "b": "None", "name": "Auth" }, { "a": "Free", "b": "Free", "name": "Pricing" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "MIT (docs and SDK)", "b": "Apache-2.0", "name": "Licence" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-08-04", "b": "2026-09-30", "name": "Last release" }, { "a": "no document linked", "b": "no document linked", "name": "Terms last updated" }, { "a": "no document linked", "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": "159 stars, 54 npm/wk", "b": "6.4k stars", "name": "Popularity" }, { "a": "none", "b": "4.5/5 (2)", "name": "Agent reviews" } ], "faq": [ { "answer": "x402 scores 79.7 (A) on agent readiness against ACK-Pay (Agent Commerce Kit)'s 53.6 (D), and leads in every scored category.", "question": "Which is better for AI agents, ACK-Pay (Agent Commerce Kit) or x402?" }, { "answer": "No open-source release is listed for ACK-Pay (Agent Commerce Kit). x402 is open source (Apache-2.0).", "question": "Are ACK-Pay (Agent Commerce Kit) and x402 open source?" } ], "goodFor": [ { "aheadOn": null, "also": null, "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": [ "Reliability, 87 against 38", "Schema \u0026 documentation, 86 against 66", "Agent ergonomics, 84 against 47", "Security \u0026 auth, 67 against 58", "Payments \u0026 pricing, 97 against 77", "Maintenance \u0026 community, 93 against 53", "Transparency \u0026 trust, 65 against 60" ], "also": [ "Agent-ready, a grade of BB or better", "Open source" ], "goodFor": "The default for an agent paying APIs per call in stablecoins without accounts, and the protocol most sellers in this directory speak.", "slug": "x402", "watchFor": "Five validated attacks on authorisation, binding, replay and web handling (arxiv 2605.11781)" } ], "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-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/acp-vs-x402.json", "title": "Agentic Commerce Protocol (ACP) vs x402", "url": "https://www.anchorterminal.com/compare/acp-vs-x402" }, { "json": "https://www.anchorterminal.com/compare/ap2-vs-x402.json", "title": "Agent Payments Protocol (AP2) vs x402", "url": "https://www.anchorterminal.com/compare/ap2-vs-x402" }, { "json": "https://www.anchorterminal.com/compare/l402-vs-x402.json", "title": "L402 vs x402", "url": "https://www.anchorterminal.com/compare/l402-vs-x402" }, { "json": "https://www.anchorterminal.com/compare/mpp-vs-x402.json", "title": "Machine Payments Protocol (MPP) vs x402", "url": "https://www.anchorterminal.com/compare/mpp-vs-x402" } ], "scores": [ { "ack-pay": 38, "by": 49, "edge": "x402", "key": "reliability", "name": "Reliability", "weight": 16, "x402": 87 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "ack-pay": 66, "by": 20, "edge": "x402", "key": "schema", "name": "Schema \u0026 documentation", "weight": 13, "x402": 86 }, { "ack-pay": 47, "by": 37, "edge": "x402", "key": "ergonomics", "name": "Agent ergonomics", "weight": 13, "x402": 84 }, { "ack-pay": 58, "by": 9, "edge": "x402", "key": "security", "name": "Security \u0026 auth", "weight": 14, "x402": 67 }, { "ack-pay": 77, "by": 20, "edge": "x402", "key": "payments", "name": "Payments \u0026 pricing", "weight": 10, "x402": 97 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "ack-pay": 53, "by": 40, "edge": "x402", "key": "maintenance", "name": "Maintenance \u0026 community", "weight": 7, "x402": 93 }, { "ack-pay": 60, "by": 5, "edge": "x402", "key": "transparency", "name": "Transparency \u0026 trust", "weight": 7, "x402": 65 } ], "summary": "x402 scores 79.7 (A) on agent readiness against ACK-Pay (Agent Commerce Kit)'s 53.6 (D), and leads in every scored category. Both do agent payment protocols.", "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.", "x402": "No account and no protocol fee, a funded wallet is enough. Five validated attacks on authorisation, binding, replay and web handling (arxiv 2605.11781)." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/ack-pay-vs-x402", "json": "https://www.anchorterminal.com/compare/ack-pay-vs-x402.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/ack-pay-vs-x402.md", "slim": "https://www.anchorterminal.com/compare/ack-pay-vs-x402.min.md" }, "markdown": "x402 scores 79.7 (A) on agent readiness against ACK-Pay (Agent Commerce Kit)'s 53.6 (D), 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- x402: grade A, 79.7/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/x402.md · JSON https://www.anchorterminal.com/api/v1/tools/x402.json\n- All 14 pay per call comparisons: https://www.anchorterminal.com/compare/pay-per-call/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\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### x402 (A)\n\nGood for: The default for an agent paying APIs per call in stablecoins without accounts, and the protocol most sellers in this directory speak.\n\nAhead on:\n- Reliability, 87 against 38\n- Schema \u0026 documentation, 86 against 66\n- Agent ergonomics, 84 against 47\n- Security \u0026 auth, 67 against 58\n- Payments \u0026 pricing, 97 against 77\n- Maintenance \u0026 community, 93 against 53\n- Transparency \u0026 trust, 65 against 60\n\nAlso in its favour:\n- Agent-ready, a grade of BB or better\n- Open source\n\nWatch for: Five validated attacks on authorisation, binding, replay and web handling (arxiv 2605.11781)\n\n\n## Score by category\n\n| Category | Weight | ACK-Pay (Agent Commerce Kit) | x402 | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 38 | 87 | x402 +49 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 66 | 86 | x402 +20 |\n| Agent ergonomics | 13% (16.2 this run) | 47 | 84 | x402 +37 |\n| Security \u0026 auth | 14% (17.5 this run) | 58 | 67 | x402 +9 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 77 | 97 | x402 +20 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 53 | 93 | x402 +40 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 60 | 65 | x402 +5 |\n| Negative events | ≤15 | -2 | -3 | |\n| **Total** | | **53.6 · D** | **79.7 · A** | |\n\n## Facts side by side\n\n| Fact | ACK-Pay (Agent Commerce Kit) | x402 |\n| --- | --- | --- |\n| Kind | Payment protocol | Payment protocol |\n| Vendor | Catena Labs, Inc. | x402 Foundation (Linux Foundation) |\n| Hosted endpoint | no (local only) | no (local only) |\n| Transports | | |\n| Auth | None | None |\n| Pricing | Free | Free |\n| x402 | no | no |\n| Licence | MIT (docs and SDK) | Apache-2.0 |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-08-04 | 2026-09-30 |\n| Terms last updated | no document linked | no document linked |\n| Privacy policy last updated | no document linked | 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 | 6.4k stars |\n| Agent reviews | none | 4.5/5 (2) |\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**x402.** No account and no protocol fee, a funded wallet is enough. Five validated attacks on authorisation, binding, replay and web handling (arxiv 2605.11781).\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### x402\n\n1. Decode PAYMENT-REQUIRED and check amount, asset and payTo against what you expected before signing\n2. Use the upto scheme when the final price isn't known, and cap it\n3. On settlement_pending, look up the returned transaction hash before paying again\n4. Use a production facilitator for Base mainnet, x402.org/facilitator is testnet only\n5. Give the agent its own wallet with a small balance, never a treasury key\n\n## Questions\n\n### Which is better for AI agents, ACK-Pay (Agent Commerce Kit) or x402?\n\nx402 scores 79.7 (A) on agent readiness against ACK-Pay (Agent Commerce Kit)'s 53.6 (D), and leads in every scored category.\n\n### Are ACK-Pay (Agent Commerce Kit) and x402 open source?\n\nNo open-source release is listed for ACK-Pay (Agent Commerce Kit). x402 is open source (Apache-2.0).\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/ack-pay-vs-x402.json, and with the fewest tokens: https://www.anchorterminal.com/compare/ack-pay-vs-x402.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"ack-pay\", \"b\": \"x402\"}`. From a terminal: `anchor compare ack-pay x402`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/ack-pay.json and https://www.anchorterminal.com/api/v1/tools/x402.json\n\n## Other comparisons with ACK-Pay (Agent Commerce Kit) or x402\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 Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/ack-pay-vs-mpp.md)\n- [Agentic Commerce Protocol (ACP) vs x402](https://www.anchorterminal.com/compare/acp-vs-x402.md)\n- [Agent Payments Protocol (AP2) vs x402](https://www.anchorterminal.com/compare/ap2-vs-x402.md)\n- [L402 vs x402](https://www.anchorterminal.com/compare/l402-vs-x402.md)\n- [Machine Payments Protocol (MPP) vs x402](https://www.anchorterminal.com/compare/mpp-vs-x402.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-10", "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" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "ACK-Pay (Agent Commerce Kit) vs x402", "url": "" } ], "description": "x402 scores 79.7 (A) to ACK-Pay's 53.6 (D) for agent payment protocols. Prices, MCP, x402, uptime and agent notes side by side.", "facts": [ "ACK-Pay (Agent Commerce Kit) D 53.6", "x402 A 79.7", "scores" ], "h1": "ACK-Pay (Agent Commerce Kit) vs x402", "image": "https://www.anchorterminal.com/assets/og/compare-ack-pay-vs-x402.png", "path": "/compare/ack-pay-vs-x402", "published": "2026-10-01", "section": "tools", "title": "ACK-Pay vs x402 for AI agents in 2026: scores and prices", "toc": null, "updated": "2026-10-09", "url": "https://www.anchorterminal.com/compare/ack-pay-vs-x402" }, "tokens": { "markdown": 1900, "slim": 580 }, "version": 1 }