--- title: "Head-to-heads for agent checkout | Agent Ready Checkout" description: "Thirty head-to-heads for agent checkout: ACP vs UCP, x402 vs MPP, Stripe vs Adyen, ChatGPT vs Google AI Mode, with a sourced difference and verdicts." canonical: https://agentreadycheckout.com/compare site: "Agent Ready Checkout" last_updated: 2026-11-04 section: "Head-to-heads" --- # Head-to-heads for agent checkout | Agent Ready Checkout > Thirty head-to-heads for agent checkout: ACP vs UCP, x402 vs MPP, Stripe vs Adyen, ChatGPT vs Google AI Mode, with a sourced difference and verdicts. Source: https://agentreadycheckout.com/compare Site: Agent Ready Checkout Last reviewed: 2026-11-04 # Head-to-heads In short 30 head-to-heads, each with one sourced difference, verdicts by reader type and a side-by-side of matrix status. The pairs cover protocols, processors, platforms and agent surfaces: ACP and UCP, x402 and MPP, Stripe and Adyen, ChatGPT shopping and Google AI Mode, and more. ## Protocols and programs - [**ACP vs UCP**](https://agentreadycheckout.com/compare/acp-vs-ucp) ACP lost its main checkout surface when OpenAI moved ChatGPT purchases to merchant sites on 24 Mar 2026 and now carries product feeds there. - [**UCP vs AP2**](https://agentreadycheckout.com/compare/ucp-vs-ap2) UCP is a commerce protocol with carts, checkout sessions and payment handlers; AP2 is a payment authorisation layer of signed mandates that UCP lists as a built-in extension. - [**Visa TAP vs Mastercard Agent Pay**](https://agentreadycheckout.com/compare/visa-trusted-agent-protocol-vs-mastercard-agent-pay) Both sign agent requests with Web Bot Auth (HTTP Message Signatures) so a CDN can verify the agent. - [**x402 vs MPP**](https://agentreadycheckout.com/compare/x402-vs-mpp) Both answer HTTP 402. x402 is governed by the x402 Foundation under the Linux Foundation (40 members at the 14 Jul 2026 launch) and settles mostly in stablecoins. - [**ACP vs AP2**](https://agentreadycheckout.com/compare/acp-vs-ap2) ACP specifies checkout endpoints a merchant hosts (create, update, complete a session) and a delegated payment token; AP2 specifies signed mandates that prove what the user authorised. - [**Visa IC vs Mastercard Agent Pay**](https://agentreadycheckout.com/compare/visa-intelligent-commerce-vs-mastercard-agent-pay) Visa has written agentic duties into its public Core Rules (section 4.1.23, April 2026) and runs Intelligent Commerce Connect in pilot for TAP, MPP, ACP and UCP traffic. - [**Mastercard Agent Pay vs Agent Pay for Machines**](https://agentreadycheckout.com/compare/mastercard-agent-pay-vs-agent-pay-for-machines) Agent Pay tokenises a consumer card for an agent buying at merchants. - [**AP2 vs Verifiable Intent**](https://agentreadycheckout.com/compare/ap2-vs-verifiable-intent) AP2 defines the mandate flow between agent, merchant and credential provider; Verifiable Intent defines a credential format (layered SD-JWT) for the same delegation. - [**x402 vs Agent Pay for Machines**](https://agentreadycheckout.com/compare/x402-vs-agent-pay-for-machines) x402 is an open protocol anyone can implement with a facilitator such as Coinbase (first 1,000 transactions free, then $0.001). - [**Amex ACE vs Mastercard Agent Pay**](https://agentreadycheckout.com/compare/amex-ace-vs-mastercard-agent-pay) Amex ACE announced Agent Purchase Protection for charges caused by agent error when a registered agent sent authenticated intent. - [**Visa TAP vs Visa IC**](https://agentreadycheckout.com/compare/visa-trusted-agent-protocol-vs-visa-intelligent-commerce) TAP tells a merchant which agent is calling; Visa Intelligent Commerce supplies the tokenised credential and rules for the payment. - [**UCP vs x402**](https://agentreadycheckout.com/compare/ucp-vs-x402) UCP carries a retail order (items, shipping, tax, payment handler); x402 carries a single HTTP payment for a resource. ## Processors and enablers - [**Stripe vs Adyen**](https://agentreadycheckout.com/compare/stripe-vs-adyen-agentic) Stripe documents ACP, UCP, MPP, x402 and Link Agent Wallet with public pricing ($0.15 per Shared Payment Token). - [**PayPal vs Stripe**](https://agentreadycheckout.com/compare/paypal-vs-stripe) PayPal Agent Ready documents ACP (ChatGPT) and UCP (Google) paths through Braintree or Orders v2, updated 13 Oct 2026, but needs a request form. - [**Checkout.com vs Adyen**](https://agentreadycheckout.com/compare/checkout-com-vs-adyen-agentic) Checkout.com says it is a certified ACP payment handler and processes UCP via Google Pay rails, and lists TAP, AP2 and Verifiable Intent, but merchant entry is a waitlist. - [**Coinbase vs Stripe**](https://agentreadycheckout.com/compare/coinbase-vs-stripe) Coinbase runs the CDP facilitator that verifies and settles x402 payments on Base and Solana with OFAC and KYT screening, claiming over 100 million payments. - [**Crossmint vs Skyfire**](https://agentreadycheckout.com/compare/crossmint-vs-skyfire) Crossmint sells buyer-side agent checkout ($0.05 per checkout after 1,000 a month) that uses Visa and Mastercard agent tokens or Shop Pay and UCP paths. - [**Skyfire vs PayOS**](https://agentreadycheckout.com/compare/skyfire-vs-payos) Skyfire combines agent identity and payment in one signed token with its own settlement. - [**Braintree vs PayPal**](https://agentreadycheckout.com/compare/braintree-vs-paypal) Braintree (now PayPal Enterprise Payments) is the processor in PayPal Agent Ready's ACP path and one of two UCP paths. - [**Worldpay vs Adyen**](https://agentreadycheckout.com/compare/worldpay-vs-adyen-agentic) Worldpay (Global Payments) says it works across ACP and UCP and collaborates on Visa TAP, but publishes no agentic developer docs; Adyen publishes ACP and UCP docs and named Amex. ## Everything else: surfaces, platforms and mixed pairs - [**Shopify vs Amazon Rufus**](https://agentreadycheckout.com/compare/shopify-vs-amazon-rufus-and-buy-for-me) Shopify opens its catalog and checkout to any registered agent (self-serve agent profiles since 17 Jun 2026, Shop MCP since 13 Oct 2026). - [**ChatGPT vs Google AI Mode**](https://agentreadycheckout.com/compare/chatgpt-shopping-vs-google-ai-mode-and-gemini-checkout) Google completes checkout inside AI Mode and Gemini over UCP with Google Wallet for select merchants, merchant of record unchanged. - [**Link for agents vs PayPal**](https://agentreadycheckout.com/compare/stripe-link-for-agents-vs-paypal) Link Agent Wallet gives an agent a one-time credential after the user approves a spend request and powers Meta Muse checkout. - [**Copilot vs Google AI Mode**](https://agentreadycheckout.com/compare/microsoft-copilot-vs-google-ai-mode-and-gemini-checkout) Both check out inside the assistant with the merchant as seller. - [**Perplexity vs ChatGPT**](https://agentreadycheckout.com/compare/perplexity-shopping-vs-chatgpt-shopping) Perplexity still checks out in chat through PayPal Instant Buy (since 25 Nov 2025) with the retailer as merchant of record. - [**Meta Muse vs Amazon Rufus**](https://agentreadycheckout.com/compare/meta-muse-vs-amazon-rufus-and-buy-for-me) Muse (8 Sep 2026) pays with Link single-use cards on other merchants' sites and was blocked by Amazon on 20 Sep 2026 for not identifying itself. - [**Shopify vs BigCommerce**](https://agentreadycheckout.com/compare/shopify-vs-bigcommerce) Shopify serves UCP Cart, Checkout and Order MCP servers for every store and Agentic Storefronts across ChatGPT, Copilot and Google. - [**Salesforce CC vs commercetools**](https://agentreadycheckout.com/compare/salesforce-commerce-cloud-vs-commercetools) Salesforce lists UCP Integration as GA in October 2026 for Gemini and AI Mode checkout. commercetools made AI Hub GA on 30 Jul 2026 with UCP checkout in Gemini - [**Adobe Commerce vs WooCommerce**](https://agentreadycheckout.com/compare/adobe-commerce-vs-woocommerce) Neither has shipped native agent checkout. - [**Shopify vs WooCommerce**](https://agentreadycheckout.com/compare/shopify-vs-woocommerce) Shopify stores answer /.well-known/ucp today (for example allbirds.com on 4 Nov 2026) and are enrolled in agent channels from Admin. ## Sources 1. [Powering Product Discovery in ChatGPT](https://openai.com/index/powering-product-discovery-in-chatgpt/), read 4 Nov 2026 2. [ucp.dev/](https://ucp.dev/), read 4 Nov 2026 3. [Cloudflare: Secure agentic commerce](https://blog.cloudflare.com/secure-agentic-commerce/), read 4 Nov 2026 4. [Machine Payments Protocol](https://mpp.dev/), read 4 Nov 2026 5. [adyen.com/press-and-media/adyen-agentic](https://www.adyen.com/press-and-media/adyen-agentic), read 4 Nov 2026 6. [shopify.dev/docs/agents](https://shopify.dev/docs/agents), read 4 Nov 2026 7. [Merchant Center help: UCP-powered checkout](https://support.google.com/merchants/answer/16837055), read 4 Nov 2026 8. [ACP repository README](https://github.com/agentic-commerce-protocol/agentic-commerce-protocol), read 4 Nov 2026 9. [Visa Core Rules and Visa Product and Service Rules, 24 October 2026](https://usa.visa.com/dam/VCOM/download/about-visa/visa-rules-public.pdf), read 4 Nov 2026 10. [Mastercard launches Agent Pay for Machines](https://www.mastercard.com/us/en/news-and-trends/press/2026/june/mastercard-launches-agent-pay-for-machines.html), read 4 Nov 2026 11. [FIDO Alliance to develop standards for trusted AI agent interactions](https://fidoalliance.org/fido-alliance-to-develop-standards-for-trusted-ai-agent-interactions/), read 4 Nov 2026 12. [Watch Mastercard Agent Pay for Machines in action](https://www.mastercard.com/global/en/news-and-trends/press/2026/october/Mastercard-Agent-Pay-for-Machines-in-action.html), read 4 Nov 2026 13. [Stripe Link Agent Wallet docs](https://docs.stripe.com/agentic-commerce/agents/link-agent-wallet), read 4 Nov 2026 14. [developer.paypal.com/agent-ready/overview](https://developer.paypal.com/agent-ready/overview), read 4 Nov 2026 15. [checkout.com/agentic-commerce](https://www.checkout.com/agentic-commerce), read 4 Nov 2026 16. [docs.cdp.coinbase.com/x402/core-concepts/facilitator](https://docs.cdp.coinbase.com/x402/core-concepts/facilitator), read 4 Nov 2026 17. [crossmint.com/pricing](https://www.crossmint.com/pricing), read 4 Nov 2026 18. [docs.skyfire.xyz/docs/payments-settlement.md](https://docs.skyfire.xyz/docs/payments-settlement.md), read 4 Nov 2026 19. [Agentic Commerce, Microsoft Advertising](https://about.ads.microsoft.com/en/solutions/technology/agentic-commerce), read 4 Nov 2026 20. [PayPal and Perplexity Launch Instant Buy](https://newsroom.paypal-corp.com/2025-11-PayPal-and-Perplexity-Launch-Instant-Buy), read 4 Nov 2026 21. [Amazon blocks Meta's Muse agent from shopping on users' behalf](https://siliconangle.com/2026/09/21/amazon-blocks-metas-muse-agent-from-shopping-on-users-behalf/), read 4 Nov 2026 22. [bigcommerce.com/articles/ecommerce/google-agentic-checkout/](https://www.bigcommerce.com/articles/ecommerce/google-agentic-checkout/), read 4 Nov 2026 23. [docs.commercetools.com/api/releases/2026-07-30-ai-hub-is-now-generally-available](https://docs.commercetools.com/api/releases/2026-07-30-ai-hub-is-now-generally-available), read 4 Nov 2026 24. [experienceleague.adobe.com/en/docs/commerce/information-center/insights-and-guidance/architectural-foundations-agentic-c](https://experienceleague.adobe.com/en/docs/commerce/information-center/insights-and-guidance/architectural-foundations-agentic-commerce), read 4 Nov 2026 25. [woocommerce.com/agentic-commerce/](https://woocommerce.com/agentic-commerce/), read 4 Nov 2026 26. [Amex Agentic Commerce Experiences](https://www.americanexpress.com/en-us/company/agentic-commerce/), read 4 Nov 2026 27. [Visa opens the door to AI-driven shopping (Intelligent Commerce Connect)](https://www.visa.co.uk/about-visa/newsroom/press-releases.3442048.html), read 4 Nov 2026 28. [shopify.com/news/ai-commerce-at-scale](https://www.shopify.com/news/ai-commerce-at-scale), read 4 Nov 2026 29. [docs.adyen.com/online-payments/agentic-commerce/agent-platform](https://docs.adyen.com/online-payments/agentic-commerce/agent-platform), read 4 Nov 2026 Last reviewed 4 Nov 2026 ## Edition Matrix edition of 4 Nov 2026. Reviewed 4 Nov 2026, [29 sources](#sources-h). ## Method [How cells, sources and read dates are defined](https://agentreadycheckout.com/method)