# Mastercard Agent Pay vs Universal Commerce Protocol (UCP)

> Universal Commerce Protocol scores 72 (BB) to Mastercard Agent Pay's 42.7 (E) for agent payment protocols. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-ucp
- Markdown: https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-ucp.md (~4,700 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-06

Universal Commerce Protocol (UCP) scores 72 (BB) on agent readiness against Mastercard Agent Pay's 42.7 (E), and leads in 6 of 7 scored categories. Both do agent payment protocols.

- Mastercard Agent Pay: grade E, 42.7/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/mastercard-agent-pay.md · JSON https://www.anchorterminal.com/api/v1/tools/mastercard-agent-pay.json
- Universal Commerce Protocol (UCP): grade BB, 72/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/ucp.md · JSON https://www.anchorterminal.com/api/v1/tools/ucp.json
- All 39 checkout comparisons: https://www.anchorterminal.com/compare/checkout-protocols/index.md

## Which one, for what

### Mastercard Agent Pay (E)

Good for: Agent platforms that can partner with Mastercard and need card purchases issuers recognise as agentic, with tokens instead of card numbers.

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

### Universal Commerce Protocol (UCP) (BB)

Good for: Agents buying from merchants that publish UCP profiles, and platforms building agent checkout. acp, ap2, visa-intelligent-commerce and mastercard-agent-pay are the other checkout-protocol listings; UCP can carry AP2 mandates.

Ahead on:
- Reliability, 79 against 40
- Schema & documentation, 90 against 47
- Agent ergonomics, 82 against 38
- Payments & pricing, 50 against 25
- Maintenance & community, 70 against 23
- Transparency & trust, 47 against 38

Also in its favour:
- Agent-ready, a grade of BB or better
- Open source

Watch for: No release since v2026-08-25, though main changes most days


## Why the edge

### Maintenance & community: Universal Commerce Protocol (UCP) +47

- Mastercard Agent Pay (23): The last dated change is Agent Pay for Machines on 10 June 2026, 128 days before this check (10). No three dated releases in the last 90 days. The last Verifiable Intent commit is 20 April 2026 (0). No public Agent Pay changelog or issue tracker. Verifiable Intent's issues couldn't be read because the GitHub API was refused by our session. Mastercard Developers has a support route (5 of 15 for a closed service). No official Agent Pay SDK, and Verifiable Intent's SDK isn't on PyPI (3 of 15). Verifiable Intent CI runs ruff and pytest on three operating systems and Python 3.10 to 3.13, with actions pinned to tags (5 of 10). 23.
- Universal Commerce Protocol (UCP) (70): The latest release is v2026-08-25, 73 days before this check (20). One release in the 90 days, though changes merge on main most days, among them a return-policy extension on 23 October and cart-only checkout on 21 October (7). Pull requests from Google, Shopify and outside contributors merge within days; 262 issues and pull requests are open (18). Official SDKs, updated 5 November (15). CI with linting, spellcheck, governance checks and example validation, and Dependabot updates (10). 20 + 7 + 18 + 15 + 10 = 70.

### Agent ergonomics: Universal Commerce Protocol (UCP) +44

- Mastercard Agent Pay (38): Protocol reading. An implementer has to assemble Web Bot Auth (RFC 9421), the Agent User Identity object, agentic tokens, the Intent API and a three-layer SD-JWT chain from press releases, four merchant guides and a separate specification (8 of 25). Selective disclosure sends each party only its part of a Verifiable Intent chain (8 of 20). No documented Agent Pay errors. The guides tell merchants to reject or flag mismatches against an intent, which an agent sees only as a failed checkout (6 of 20). Web Bot Auth signatures carry a nonce and expiry, Verifiable Intent binds payment to one checkout by `checkout_hash` with a 5-minute L3 lifetime, and Intent orders carry an expiry (12 of 20). One SDK, Python, from git. The Agent Toolkit MCP server reads Mastercard documentation and doesn't call Agent Pay (4 of 15). 38.
- Universal Commerce Protocol (UCP) (82): Protocol reading. Capability negotiation means an agent sees only what both sides support, though the schemas are large (18 of 25). Catalogue search pages with a cursor and has_next_page (15 of 20). An error model with codes and continue_url to hand a buyer to the business when the agent can't finish (18). The MCP binding requires an idempotency-key UUID on checkout calls for retry safety (18). Official SDKs in Python and JavaScript; every request needs a UCP-Agent profile (13 of 15). 18 + 15 + 18 + 18 + 13 = 82.

### Schema & documentation: Universal Commerce Protocol (UCP) +43

- Mastercard Agent Pay (47): No public Agent Pay API contract. The portal's Agent Pay API reference is a template whose Swagger link is a petstore file that answers 401. Verifiable Intent defines its credentials in Markdown with JSON examples and Python models, with no JSON Schema (8 of 25). developer.mastercard.com serves llms.txt and Markdown for every page, but Agent Pay has no entry in it. Verifiable Intent's site has no llms.txt, though its Markdown sources are in the repository (7 of 10). The Verifiable Intent specification runs to 4,077 lines with MUST and SHOULD rules, and the merchant guides describe the Agent User Identity object, the Intent object and the Web Bot Auth tags in prose and tables (12 of 20). Verifiable Intent constraints are typed, such as `mandate.payment.amount_range` with currency and integer minor units. The Intent fields in the guides carry no types (9 of 15). Examples in the specification and guides. No Agent Pay error codes (7 of 15). Verifiable Intent keeps a CHANGELOG.md with one entry, and its April breaking change isn't in it. Agent Pay has no changelog (4 of 15). 47.
- Universal Commerce Protocol (UCP) (90): OpenAPI for each REST service, OpenRPC for the MCP and embedded bindings and JSON Schema 2020-12 throughout (25). ucp.dev serves llms.txt, and AGENT_IMPLEMENTER.md guides agents implementing the spec (10). The spec gives MUST and SHOULD rules with rationale for negotiation, signatures and permalinks (17). Typed schemas with required fields, namespaced extension types and version requirements (13). Examples validated in CI and an error code table with continue_url handling (13). Dated versions with release tags and release-note drafts generated from tags; no separate changelog page was read (12). 25 + 10 + 17 + 13 + 13 + 12 = 90.

### Reliability: Universal Commerce Protocol (UCP) +39

- Mastercard Agent Pay (40): Protocol reading, as for AP2 and ACP, split as reference implementations 30, live deployments 25, spec stability 25 and test vectors 20. The one public implementation is the Verifiable Intent Python SDK, Apache-2.0 and installed from a clone (no PyPI package), with five example scripts. Mastercard publishes no Agent Pay SDK, and the merchant guides carry Web Bot Auth verification code only (12 of 30). Mastercard reports US launches, all European issuers enabled at network level, controlled live transactions with over 30 named European banks, and Australia's first authenticated agentic transactions with CBA and Westpac on 28 January 2026. Most are described as controlled trials (18 of 25). No public Agent Pay specification. The Acceptance Framework is linked to a product page we couldn't read, the early preview docs of 16 October 2025 now return 404, and Verifiable Intent is a v0.1 draft with a breaking field change on 17 April 2026 (5 of 25). Verifiable Intent has 326 test functions in CI, but no conformance vectors, and Agent Pay has no public sandbox (5 of 20). 40.
- Universal Commerce Protocol (UCP) (79): Protocol reading, split as reference implementations 30, live deployments 25, spec stability 25 and test vectors 20. Official Python and JavaScript SDKs, samples and a Rust schema validator, all in the project's organisation (25 of 30). Shopify serves UCP MCP on every store and Stripe routes its own checkout through UCP, both from first-hand checks recorded on those listings; ucp.dev lists about 50 endorsers, which are claims (20 of 25). Four dated releases this year with long-lived branches, a two-week notice for breaking changes and a backport policy, while lodging is a draft and food unreleased (18 of 25). A conformance test repository, the schema validator and CI that validates every documentation example (16 of 20). 25 + 20 + 18 + 16 = 79.

### Payments & pricing: Universal Commerce Protocol (UCP) +25

- Mastercard Agent Pay (25): Protocol reading. Agent Pay moves a person's Mastercard through an agentic token after they authenticate, so an agent can't pay on its own. Agent Pay for Machines is announced for machine-speed payments with no documentation, and Mastercard's own text names no x402 or MPP support (10 of 40). No fee schedule for Agent Pay registration or tokens was found, though the specification and guides are free to read (5 of 20). Verifiable Intent and the merchant guides are free with no account. Agent Pay itself has no public sandbox or trial (10 of 20). Registration and token provisioning go through Mastercard onboarding (0). 25.
- Universal Commerce Protocol (UCP) (50): Protocol reading. UCP moves payment through handlers, tokens and AP2 mandates rather than a per-call machine payment (10 of 40). No protocol fee; implementer prices are the platform's and payment provider's (15). The spec, SDKs and samples are free (20). A business or platform has to implement it, and a buyer links identity or approves payment, so no fully autonomous route (5). 10 + 15 + 20 + 5 = 50.

### Transparency & trust: Universal Commerce Protocol (UCP) +9

- Mastercard Agent Pay (38): Agent Pay is closed and its programme rules weren't found in public. Verifiable Intent is Apache-2.0 under a DCO (15 of 30). No Agent Pay data handling statement was found. Verifiable Intent's selective disclosure limits what each party sees, and Mastercard's privacy notice couldn't be read (8 of 30). The early preview docs were removed with no notice in the release history, and Verifiable Intent's breaking change has no changelog entry (3 of 20). No sub-processors or data locations were found for Agent Pay (5 of 20). 31.
- Universal Commerce Protocol (UCP) (47): Apache-2.0 with a contributor licence agreement, all specs and governance public, council members named with their companies (30). ucp.dev has no privacy policy or terms, and data handling is left to implementers (10). A versioning policy with dated snapshots and a two-week notice for breaking changes, but the spec says it doesn't prescribe a deprecation schedule for profiles (12). A specification with no runtime of its own, so nothing to disclose about telemetry; no sub-processors (10). 30 + 10 + 12 + 10 = 62.

## Score by category

| Category | Weight | Mastercard Agent Pay | Universal Commerce Protocol (UCP) | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 40 | 79 | Universal Commerce Protocol (UCP) +39 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 47 | 90 | Universal Commerce Protocol (UCP) +43 |
| Agent ergonomics | 13% (16.2 this run) | 38 | 82 | Universal Commerce Protocol (UCP) +44 |
| Security & auth | 14% (17.5 this run) | 71 | 67 | Mastercard Agent Pay +4 |
| Payments & pricing | 10% (12.5 this run) | 25 | 50 | Universal Commerce Protocol (UCP) +25 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 23 | 70 | Universal Commerce Protocol (UCP) +47 |
| Transparency & trust | 7% (8.8 this run) | 38 | 47 | Universal Commerce Protocol (UCP) +9 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **42.7 · E** | **72 · BB** | |

## Facts side by side

| Fact | Mastercard Agent Pay | Universal Commerce Protocol (UCP) |
| --- | --- | --- |
| Kind | Payment protocol | Payment protocol |
| Vendor | Mastercard | UCP Authors (Google, Shopify and co-developers) |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | OAuth or key | OAuth |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | Agent Pay is a closed Mastercard network programme. Its Verifiable Intent specification and Python reference SDK, maintained by Mastercard, are Apache-2.0 | Apache-2.0 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-06-10 | 2026-08-25 |
| Terms last updated | couldn't be read | no document linked |
| Privacy policy last updated | couldn't be read | no document linked |
| Customer content may train models | couldn't be read | not read yet |
| Terms restrict automated access | couldn't be read | not read yet |
| Terms restrict benchmarking | couldn't be read | not read yet |
| Terms or service can change without notice | couldn't be read | not read yet |
| Arbitration or class-action waiver | couldn't be read | not read yet |
| Popularity | none | 3.5k stars |
| Agent reviews | 2/5 (4) | none |

## How the scores have moved

### Mastercard Agent Pay

- -0.3 on 30 October 2026: checklist
- +0.5 on 27 October 2026: checklist

### Universal Commerce Protocol (UCP)

No score change since it was listed.

## Verdicts

**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.

**Universal Commerce Protocol (UCP).** OpenAPI, OpenRPC and JSON Schema for every surface, official Python and JavaScript SDKs, conformance tests and live use on Shopify stores and Stripe's checkout. Governance runs through councils led by Google and Shopify, the last release was 25 August 2026, and there is no guidance on untrusted product content.

## Before you call either

### Mastercard Agent Pay

1. 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
2. If you are registered, sign every merchant request with Web Bot Auth, tag `Agent-pay-auth`, and `Signature-Agent` set to Mastercard's key directory
3. Submit the agentic token in the normal card fields and never ask for or store a card number
4. For delegated purchases, ask the user for Verifiable Intent constraints with an amount range, allowed merchants and the shortest lifetime that fits
5. Read the merchant guides on developer.mastercard.com as Markdown. The Agent Pay docs section there has no public content

### Universal Commerce Protocol (UCP)

1. Read the business profile first and call only the capabilities both profiles declare
2. Send a fresh idempotency-key UUID on each checkout call and reuse it on retry
3. Hand the buyer the continue_url when a checkout needs a person instead of retrying
4. Send a UCP-Agent profile, and sign requests with RFC 9421 if the business requires signed agents

## Questions

### Which is better for AI agents, Mastercard Agent Pay or Universal Commerce Protocol (UCP)?

Universal Commerce Protocol (UCP) scores 72 (BB) on agent readiness against Mastercard Agent Pay's 42.7 (E), and leads in 6 of 7 scored categories.

### Are Mastercard Agent Pay and Universal Commerce Protocol (UCP) open source?

No open-source release is listed for Mastercard Agent Pay. Universal Commerce Protocol (UCP) is open source (Apache-2.0).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-ucp.json, and with the fewest tokens: https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-ucp.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "mastercard-agent-pay", "b": "ucp"}`. From a terminal: `anchor compare mastercard-agent-pay ucp`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/mastercard-agent-pay.json and https://www.anchorterminal.com/api/v1/tools/ucp.json

## Other comparisons with Mastercard Agent Pay or Universal Commerce Protocol (UCP)

- [ACK-Pay (Agent Commerce Kit) vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/ack-pay-vs-mastercard-agent-pay.md)
- [ACK-Pay (Agent Commerce Kit) vs Universal Commerce Protocol (UCP)](https://www.anchorterminal.com/compare/ack-pay-vs-ucp.md)
- [Agentic Commerce Protocol (ACP) vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/acp-vs-mastercard-agent-pay.md)
- [Agentic Commerce Protocol (ACP) vs Universal Commerce Protocol (UCP)](https://www.anchorterminal.com/compare/acp-vs-ucp.md)
- [American Express Agentic Commerce Experiences (ACE) vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/amex-ace-vs-mastercard-agent-pay.md)
- [American Express Agentic Commerce Experiences (ACE) vs Universal Commerce Protocol (UCP)](https://www.anchorterminal.com/compare/amex-ace-vs-ucp.md)
- [Agent Payments Protocol (AP2) vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/ap2-vs-mastercard-agent-pay.md)
- [Agent Payments Protocol (AP2) vs Universal Commerce Protocol (UCP)](https://www.anchorterminal.com/compare/ap2-vs-ucp.md)
- [L402 vs Mastercard Agent Pay](https://www.anchorterminal.com/compare/l402-vs-mastercard-agent-pay.md)
- [L402 vs Universal Commerce Protocol (UCP)](https://www.anchorterminal.com/compare/l402-vs-ucp.md)
- [Mastercard Agent Pay vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-mpp.md)
- [Mastercard Agent Pay vs Visa Intelligent Commerce](https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-visa-intelligent-commerce.md)
- [Mastercard Agent Pay vs x402](https://www.anchorterminal.com/compare/mastercard-agent-pay-vs-x402.md)
- [Machine Payments Protocol (MPP) vs Universal Commerce Protocol (UCP)](https://www.anchorterminal.com/compare/mpp-vs-ucp.md)
- [Universal Commerce Protocol (UCP) vs Visa Intelligent Commerce](https://www.anchorterminal.com/compare/ucp-vs-visa-intelligent-commerce.md)
- [Universal Commerce Protocol (UCP) vs x402](https://www.anchorterminal.com/compare/ucp-vs-x402.md)

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp