Building the Universal Commerce Protocol (2026) - Shopify

What this post added

This post introduces the Universal Commerce Protocol (UCP), an open standard co-developed with Google for AI agents to interact with merchants. It details UCP's layered architecture (Shopping Service, Capabilities, Extensions), its discovery and negotiation mechanisms based on merchant and agent profiles, and its approach to handling complex commerce scenarios like fulfillment and payments. The protocol supports graceful handoffs for transactions requiring human input via an Embedded Checkout Protocol (ECP) and emphasizes flexibility through domain-specific extensions and namespace ownership via reverse-domain naming. The post also highlights the payment negotiation process and the collaborative nature of the protocol's evolution.