Google and Shopify’s agentic commerce protocol adds grocery, 3D Secure and split payments

The Universal Commerce Protocol (UCP), the open standard backed by Google and Shopify for letting AI agents browse, buy and pay on a shopper’s behalf, has published its largest update since April. Release v2026-08-25, announced on the project’s site and covered by Search Engine Journal on August 31, reorganizes the specification into Shopping, Payment and Common domains, adds grocery-specific capabilities, and introduces a set of payment features that merchants had flagged as missing.

On the payments side, the release brings vendor-neutral 3D Secure 2 authentication, so an agent-initiated purchase can pass a bank’s strong customer authentication challenge without being tied to one processor. It also adds split payments across several instruments, payment schedules covering deposits, installments and deferred charges, and a separation of raw card numbers from network tokens as distinct credential types.

Grocery gets its own tooling: store location search with geocoding, standardized opening hours with time-zone handling, and fractional quantities priced by weight, the building block needed for an agent to order 1.2 kilos of apples rather than a single SKU. Several changes are breaking. Fulfillment schemas were restructured, buyer consent moved to a dynamic mapping, profile signing keys were consolidated into a single JWK set, and payment extensions migrated from the shopping namespace to a common one.

Why it matters

UCP is quickly becoming the plumbing beneath agentic shopping in Google’s AI Mode and in Shopify’s checkout. Its governance has widened through 2026: Stripe joined the governing council in April alongside permanent members Google and Shopify, the technical committee expanded to 16 seats including Amazon, Meta, Microsoft and Salesforce, and vertical councils for food (Block, DoorDash, Toast, Uber Eats) and lodging (Amadeus, Booking.com, Expedia, Hilton, Marriott, Trip.com) formed in July and August. For retailers, the practical message is that AI checkout is no longer an experiment with a stable API; it is a living standard with breaking releases every few months, and integration budgets should reflect that.

What’s next

The project says this release lays the groundwork for full food ordering, including menu selection and tipping, and for hotel search and reservations, without giving dates. Merchants on Shopify will get most of the changes through the platform, but brands running their own storefronts or marketplaces will need to review the migration notes before the next Google or Stripe agent surface starts requiring the new schemas.