Agent Ready CheckoutEdition . The pay layer for agents.

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
    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
    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
    Both sign agent requests with Web Bot Auth (HTTP Message Signatures) so a CDN can verify the agent.
  • 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
    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
    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
    Agent Pay tokenises a consumer card for an agent buying at merchants.
  • 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
    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
    Amex ACE announced Agent Purchase Protection for charges caused by agent error when a registered agent sent authenticated intent.
  • Visa TAP vs Visa IC
    TAP tells a merchant which agent is calling; Visa Intelligent Commerce supplies the tokenised credential and rules for the payment.
  • 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
    Stripe documents ACP, UCP, MPP, x402 and Link Agent Wallet with public pricing ($0.15 per Shared Payment Token).
  • 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
    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
    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
    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
    Skyfire combines agent identity and payment in one signed token with its own settlement.
  • 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
    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
    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
    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
    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
    Both check out inside the assistant with the merchant as seller.
  • Perplexity vs ChatGPT
    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
    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
    Shopify serves UCP Cart, Checkout and Order MCP servers for every store and Agentic Storefronts across ChatGPT, Copilot and Google.
  • Salesforce CC 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
    Neither has shipped native agent checkout.
  • 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, read 4 Nov 2026
  2. ucp.dev/, read 4 Nov 2026
  3. Cloudflare: Secure agentic commerce, read 4 Nov 2026
  4. Machine Payments Protocol, read 4 Nov 2026
  5. adyen.com/press-and-media/adyen-agentic, read 4 Nov 2026
  6. shopify.dev/docs/agents, read 4 Nov 2026
  7. Merchant Center help: UCP-powered checkout, read 4 Nov 2026
  8. ACP repository README, read 4 Nov 2026
  9. Visa Core Rules and Visa Product and Service Rules, 24 October 2026, read 4 Nov 2026
  10. Mastercard launches Agent Pay for Machines, read 4 Nov 2026
  11. FIDO Alliance to develop standards for trusted AI agent interactions, read 4 Nov 2026
  12. Watch Mastercard Agent Pay for Machines in action, read 4 Nov 2026
  13. Stripe Link Agent Wallet docs, read 4 Nov 2026
  14. developer.paypal.com/agent-ready/overview, read 4 Nov 2026
  15. checkout.com/agentic-commerce, read 4 Nov 2026
  16. docs.cdp.coinbase.com/x402/core-concepts/facilitator, read 4 Nov 2026
  17. crossmint.com/pricing, read 4 Nov 2026
  18. docs.skyfire.xyz/docs/payments-settlement.md, read 4 Nov 2026
  19. Agentic Commerce, Microsoft Advertising, read 4 Nov 2026
  20. PayPal and Perplexity Launch Instant Buy, read 4 Nov 2026
  21. Amazon blocks Meta's Muse agent from shopping on users' behalf, read 4 Nov 2026
  22. 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, read 4 Nov 2026
  24. experienceleague.adobe.com/en/docs/commerce/information-center/insights-and-guidance/architectural-foundations-agentic-c, read 4 Nov 2026
  25. woocommerce.com/agentic-commerce/, read 4 Nov 2026
  26. Amex Agentic Commerce Experiences, read 4 Nov 2026
  27. Visa opens the door to AI-driven shopping (Intelligent Commerce Connect), read 4 Nov 2026
  28. shopify.com/news/ai-commerce-at-scale, read 4 Nov 2026
  29. docs.adyen.com/online-payments/agentic-commerce/agent-platform, read 4 Nov 2026

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