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Universal Commerce Protocol / reference

The standard for commerce that AI agents can read, negotiate, and act on.

Launched by Google and Shopify at NRF 2026, the open UCP standard connects catalog, cart, and payment to AI agents. This hub documents the protocol for technical and strategic decisions.

Assess my readiness Understand the standard Implement UCP →

UCP cycle, functional reading

A merchant journey an agent can read.

This diagram summarizes the surfaces documented in this registry. It does not replace the UCP specification or implementation-specific controls.

  1. 01 / Catalog

    Product and offer data

  2. 02 / Cart

    Intent and selection

  3. 03 / Checkout

    Confirmation and policies

  4. 04 / Order

    Execution and tracking

Verification desk / 2026-08-27

Authority built on evidence anyone can inspect.

Sources14 primary referencesPublic register and reusable JSON Tracked releaseUCP 2026-08-25Separated, sourced statuses Public toolProfile preflightLocal, private, no sign-up

The standard

UCP, in four verifiable facts.

Every claim on this hub is sourced and dated. Details, milestones and primary sources live on the standard reference page.

01

An open standard, led by Google and Shopify.

Announced January 11, 2026 at NRF, co-developed with Etsy, Wayfair, Target and Walmart, endorsed by 20+ players (Adyen, American Express, Mastercard, Stripe, Visa...). Public specification on GitHub.

02

Native checkout in AI Mode and Gemini.

Google's reference implementation lets consumers buy directly inside the conversation, with Google Pay. The merchant remains the merchant of record.

03

Rapid expansion since May 2026.

Google Marketing Live 2026: multi-retailer Universal Cart, Affirm and Klarna buy-now-pay-later inside Google Pay, Shopping ads on YouTube. In June 2026, first Asia-Pacific market (Australia) and 150+ agentic updates on the Shopify side (Editions Spring 26).

04

Not the only standard: UCP coexists with ACP.

OpenAI and Stripe push the Agentic Commerce Protocol on the ChatGPT side. In June 2026, OpenAI scaled back its native checkout and partnered with Visa for payments. Compared point by point in UCP vs ACP.

The reading framework

Three shifts are happening simultaneously.

01

Product data is no longer optimized solely for humans.

Agents read at machine speed, reason about intent and act on behalf of the buyer. A "well-written" product page is no longer enough: a semantic contract is needed.

02

A protocol layer is missing from the commerce stack.

Between merchant, agent and platform, there is no shared contract for offers, inventory, policies and intent. It is emerging, in fragments, through MCP, schema.org, GS1, Stripe ACP, Visa IC.

03

Merchant readiness becomes the decisive variable.

Platforms will deliver most of the plumbing. Catalog quality, attribute richness and policy clarity remain the operator's responsibility, and that is where the advantage lies.

Read the full argument →

The framework

Four layers,
one contract.

The UCP framework breaks down the stack into four layers that an operator can map, score and prioritize.

Explore the four layers
  1. I

    Semantic Layer

    Catalog data becomes machine-addressable.

    Product, Offer, Policy, Availability: a stable semantic contract that agents can parse, compare and cite, beyond HTML optimized for Google.

  2. II

    Agent Layer

    Agents interact with merchants deterministically.

    Typed endpoints, tools exposed via MCP/A2A, action and query surfaces. An agent must be able to read, propose, and confirm.

  3. III

    Transaction Layer

    Payment and identity are compatible with a delegated buyer.

    Agentic rails (Stripe ACP, Visa Intelligent Commerce...), pre-authorized intents, limits, traceability. Purchasing is no longer a human plus a browser.

  4. IV

    Governance Layer

    The operator retains control: rules, consent, audit.

    Pricing policies, eligibility, territories, dispute, retention. What the merchant authorizes, refuses, revises, in a readable and versioned manner.

Who this hub is for

For those who make 18-month decisions, not those looking for a weekly hack.

01

E-commerce & retail leaders

CEO, CMO, Chief Digital seeking a stable analytical framework.

02

Commerce platforms & SaaS

PMs and founders who need to position their roadmap against the rise of agents.

03

Innovation teams

Teams tasked with anticipating the reshaping of discovery and checkout.

04

Analysts, funds, media

Observers looking for a usable, credible conceptual framework.

See target profiles in detail →

Editorial principles

What sets this hub apart from a generic blog.

The .fr is not a media outlet. News, analysis and long-form resources live on the editorial outlet .blog. Here, only: framework, method, application.

01 Platform neutrality.
Neither Stripe, nor Shopify, nor OpenAI. Players are cited on merit.
02 Epistemic honesty.
Every claim is labeled established / emerging / prospective.
03 Operational utility.
The framework translates into decisions that can be made in a strategy meeting.
04 Stabilized vocabulary.
One concept, one translation, reused everywhere.
  • 01Standard reference
  • 02Platform-neutral
  • 03Claim-tagged
  • 04Multilingual

Reference notes

The latest technical analyses of the protocol

Evergreen answers verified against the official specifications and revised in place.

All reference notes →
  1. 01 How to validate a UCP implementation before production A UCP validation plan for discovery, negotiation, schemas, states, signatures, idempotency, security, and end-to-end tests.
  2. 02 UCP extensions: names, parents and versions Declare UCP extensions: names, parents, versions and schemas. Learn why Discount can remain negotiable with Checkout alone, under conditions.
  3. 03 UCP errors, retries, and idempotency in production Separate UCP transport errors from business results, handle 409, 429, and 503, then retry without duplicating a transaction.

UCP readiness diagnostic

Start with facts,
not a meeting.

12 factual checks, a transparent score, and an instant action plan. Calculation stays in your browser and requires no account.

Run the diagnostic View the methodology

A local ledger

12 checks

Catalog, transaction, trust, and operations.

24 readable points

0, 1, or 2 points with no hidden weighting.

Optional human review

Contact only if you choose to explore the result further.

Practical guides