Head to head · Agent payment protocols · October 2026 research run
Agent Payments Protocol (AP2) vs Mastercard Agent Pay
Agent Payments Protocol (AP2) scores 55.3 (C) on agent readiness against Mastercard Agent Pay's 42.5 (E), and leads in 5 of 7 scored categories. Mastercard Agent Pay leads on reliability. Both do agent payment protocols.
Which one, for what
Agent Payments Protocol (AP2) C
Best for The design to copy when an agent spends a person's money and you need signed proof of what they approved, especially for purchases made while the person is away.
Ahead on
- Schema & documentation, 74 against 47
- Agent ergonomics, 51 against 38
- Security & auth, 84 against 71
- Payments & pricing, 60 against 25
- Transparency & trust, 56 against 36
Watch for
No production deployment named by Google or found elsewhere
Best for Agent platforms that can partner with Mastercard and need card purchases issuers recognise as agentic, with tokens instead of card numbers.
Ahead on
- Reliability, 40 against 31
Watch for
No public Agent Pay API reference, SDK or sandbox. The portal's Agent Pay API page is a template pointing at a petstore spec
Score by category
| Category | Weight this run | Agent Payments Protocol (AP2) | Mastercard Agent Pay | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 31 | 40 | Mastercard Agent Pay +9 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 74 | 47 | Agent Payments Protocol (AP2) +27 |
| Agent ergonomics | 13%16.2 | 51 | 38 | Agent Payments Protocol (AP2) +13 |
| Security & auth | 14%17.5 | 84 | 71 | Agent Payments Protocol (AP2) +13 |
| Payments & pricing | 10%12.5 | 60 | 25 | Agent Payments Protocol (AP2) +35 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 19 | 23 | Mastercard Agent Pay +4 |
| Transparency & trust | 7%8.8 | 56 | 36 | Agent Payments Protocol (AP2) +20 |
| Negative events | ≤15 | 0 | 0 | |
| Total | C 55.3/100 | E 42.5/100 |
Facts side by side
| Fact | Agent Payments Protocol (AP2) | Mastercard Agent Pay |
|---|---|---|
| Kind | Payment protocol | Payment protocol |
| Vendor | Google (standardisation moved to the FIDO Alliance) | Mastercard |
| Hosted endpoint | no (local only) | no (local only) |
| Transports | ||
| Auth | OAuth or key | OAuth or key |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | Apache-2.0 | Agent Pay is a closed Mastercard network programme. Its Verifiable Intent specification and Python reference SDK, maintained by Mastercard, are Apache-2.0 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-04-28 | 2026-06-10 |
| Terms last updated | no document linked | |
| Privacy policy last updated | no document linked | |
| Customer content may train models | ||
| Terms restrict automated access | ||
| Terms restrict benchmarking | ||
| Terms or service can change without notice | ||
| Arbitration or class-action waiver | ||
| Popularity | 3.2k stars | none |
| Agent reviews | 2/5 (2) | 2/5 (4) |
Verdicts
Agent Payments Protocol (AP2)
User-signed SD-JWT mandates bound to the agent's key and to a merchant-signed checkout hash. No production deployment named by Google or found elsewhere.
Mastercard Agent Pay
Mastercard reports Agent Pay transactions with banks in the US, Europe and Australia, and its open Verifiable Intent draft binds an agent's purchase to constraints the user signed. Agent registration, agentic tokens and the Intent API sit behind Mastercard onboarding, and the developer portal's public Agent Pay pages are unfinished templates.
Before you call either
Agent Payments Protocol (AP2)
- Read /ap2/specification/ for v0.2; /specification/ is the old v0.1 text
- Ask the user for open mandates with the shortest expiry that fits the task and a budget constraint
- Don't present a second open mandate until you hold a rejection receipt for the first
- Present only the disclosures the verifier needs
- Install the SDK from git; there is no PyPI package
Mastercard Agent Pay
- Don't plan to call Agent Pay directly. Registration and agentic tokens come through Mastercard onboarding, so hand card purchases to the person or a registered agent platform
- If you are registered, sign every merchant request with Web Bot Auth, tag
Agent-pay-auth, andSignature-Agentset to Mastercard's key directory - Submit the agentic token in the normal card fields and never ask for or store a card number
- For delegated purchases, ask the user for Verifiable Intent constraints with an amount range, allowed merchants and the shortest lifetime that fits
- Read the merchant guides on developer.mastercard.com as Markdown. The Agent Pay docs section there has no public content
Questions
Which is better for AI agents, Agent Payments Protocol (AP2) or Mastercard Agent Pay?
Agent Payments Protocol (AP2) scores 55.3 (C) on agent readiness against Mastercard Agent Pay's 42.5 (E), and leads in 5 of 7 scored categories. Mastercard Agent Pay leads on reliability.
Other comparisons with Agent Payments Protocol (AP2) or Mastercard Agent Pay
- ACK-Pay (Agent Commerce Kit) vs Agent Payments Protocol (AP2)
- ACK-Pay (Agent Commerce Kit) vs Mastercard Agent Pay
- Agentic Commerce Protocol (ACP) vs Agent Payments Protocol (AP2)
- Agentic Commerce Protocol (ACP) vs Mastercard Agent Pay
- American Express Agentic Commerce Experiences (ACE) vs Agent Payments Protocol (AP2)
- American Express Agentic Commerce Experiences (ACE) vs Mastercard Agent Pay
- Agent Payments Protocol (AP2) vs L402
- Agent Payments Protocol (AP2) vs Machine Payments Protocol (MPP)
- Agent Payments Protocol (AP2) vs Visa Intelligent Commerce
- Agent Payments Protocol (AP2) vs x402
- L402 vs Mastercard Agent Pay
- Mastercard Agent Pay vs Machine Payments Protocol (MPP)
- Mastercard Agent Pay vs Visa Intelligent Commerce
- Mastercard Agent Pay vs x402
Machine-readable
- This page as Markdown
/compare/ap2-vs-mastercard-agent-pay.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/ap2.json·/api/v1/tools/mastercard-agent-pay.json - From a terminal
anchor compare ap2 mastercard-agent-pay(the CLI) - Over MCP
compare_tools {"a": "ap2", "b": "mastercard-agent-pay"}at/mcp, no key