What changed
Shopify announced on October 9 that its Global Catalog REST API, deprecated in April, will stop serving traffic on November 2, 2026. Requests to discover.shopifyapps.com/global/... will fail, including those against saved catalogs. Shopify directs developers to Global Catalog MCP, implementing Universal Commerce Protocol (UCP) catalog tools at catalog.shopify.com/api/ucp/mcp. The migration requires changing REST routes to search_catalog, lookup_catalog and get_product, sending a UCP agent profile in request metadata, and adopting the new request/response schemas.
Why it matters
Cross-store product search is a key building block for shopping agents and affiliate/discovery tools. This is a hard endpoint cutoff rather than an optional version upgrade: unchanged integrations will lose search and product-lookup capability. The move also signals a platform-level shift from bespoke REST endpoints to discoverable, agent-oriented UCP/MCP tools, while preserving existing bearer-token authentication.
Endpoint retirement is absolute
Shopify's notice explicitly lists the four affected REST routes and says requests to the old global domain stop being served. Existing saved-catalog URLs are included; this is not limited to new integrations.
Migration is a protocol and schema change
Search maps to search_catalog; product and variant lookup maps to get_product with Shopify GIDs; bulk lookup maps to lookup_catalog. Saved-catalog identity moves into catalog.catalog_id, and requests must declare an agent profile. UCP catalog schemas and tool results differ from the old REST shapes.
What stays and what changes
Bearer-token issuance through Dev Dashboard remains. But application code that assumes REST paths, direct JSON response formats or implicit agent capabilities must be adapted and tested against the MCP endpoint. Shopify provides an AI Toolkit and UCP CLI for test queries.