Shopify Global Catalog vs Walmart Affiliate API for AI agents
Shopify Global Catalog is a set of Shopify MCP servers that let AI agents search products across all Shopify merchants (Global Catalog) or within one store (Storefront Catalog), with cart and checkout tools, built on the Universal Commerce Protocol (UCP). Walmart Affiliate API is Walmart I/O's set of REST services for affiliates to search Walmart.com products and earn referral fees.
The short answer
- Shopify Global Catalog: AI agents that want to search many independent Shopify stores at once and hand the shopper a real merchant checkout link.
- Walmart Affiliate API: Affiliate publishers in the Impact network who want live Walmart.com prices and availability with tracked links.
Side by side
| Shopify Global Catalog | Walmart Affiliate API | |
|---|---|---|
| Searches | Products across the whole Shopify ecosystem by text, image or similar-product IDs, with filters such as price, shop, shipping and category; or one merchant's catalog at https://{storedomain}/api/ucp/mcp. | Text search of the Walmart.com catalogue for items sold online, item lookup by item ID or UPC, taxonomy, reviews, trending items and recommendations; several categories are excluded. |
| Returns | Results grouped by Universal Product ID with offers from multiple merchants; get_product returns pricing and the seller's checkout link for the chosen variant. | Item data including real-time price and availability; a responseGroup parameter sets which item fields come back. |
| Before the first call | No API key: every request must reference a hosted UCP agent profile. Higher limits and checkout completion need a credential from Shopify's Dev Dashboard (Token tier); anonymous traffic shares one limit and is not for production. | A Walmart.com account to log in to walmart.io, a registered application with an uploaded public key (which creates a consumer ID), and an Impact Radius publisher ID passed on calls. |
| Free | No key needed, and its pages state no price | Not stated on its pages |
| Acting on a result | Checkout link to the merchant's own checkout (one per store); agents at the highest trust tier can complete checkout through the Checkout MCP. | Affiliate links: calls carry your Impact Radius publisher ID and you earn referral fees when shoppers buy on Walmart.com. |
| Coverage | Not stated on its pages | Walmart.com (United States). |
| MCP server | Official Global Catalog MCP at https://catalog.shopify.com/api/ucp/mcp; per-store Storefront Catalog MCP at https://{storedomain}/api/ucp/mcp. | No official server listed |
Where Openpath fits
Openpath has no products listed yet. Sellers can list a product on Openpath today, free, and agents will find it through the same search as jobs and businesses. Get listed.
Questions people ask
What do I need before I can use Shopify Global Catalog?
No API key: every request must reference a hosted UCP agent profile. Higher limits and checkout completion need a credential from Shopify's Dev Dashboard (Token tier); anonymous traffic shares one limit and is not for production.
Is Shopify Global Catalog free?
No key needed, and its pages state no price.
What do I need before I can use Walmart Affiliate API?
A Walmart.com account to log in to walmart.io, a registered application with an uploaded public key (which creates a consumer ID), and an Impact Radius publisher ID passed on calls.
Is Walmart Affiliate API free?
Its pages listed no free use when we read them on October 15, 2026.
Sources
Every line about another company comes from its own pages. Prices and terms change, so check the source before you rely on one.
Shopify Global Catalog, read on October 15, 2026:
- shopify.dev/docs/agents/catalog/global-catalog: “The Global Catalog MCP server enables AI agents to search and discover products across the entire Shopify ecosystem”
- shopify.dev/docs/agents/catalog/global-catalog: “Results are clustered by Universal Product ID (UPID) and include offers from multiple merchants.”
- shopify.dev/docs/agents/catalog/global-catalog: “pricing and seller checkout links for the buyer's chosen variant”
- shopify.dev/docs/agents/catalog/global-catalog: “The `/api/ucp/mcp` endpoint requires an agent profile.”
- shopify.dev/docs/agents/catalog/storefront-catalog: “enables AI agents to search and discover products from a single merchant's catalog”
- shopify.dev/docs/agents: “Higher trust tiers unlock broader access, including direct checkout completion.”
- shopify.dev/docs/agents/profiles/auth-and-rate-limiting: “Agents authenticating with a credential issued through Dev Dashboard”
- shopify.dev/docs/agents/profiles/auth-and-rate-limiting: “The default limit is 5 requests each second for each API client.”
- shopify.dev/docs/agents/profiles/auth-and-rate-limiting: “Don't use unauthenticated requests for production traffic.”
Walmart Affiliate API, read on October 15, 2026:
- walmart.io/apidocs/affiliates/introduction: “a useful collection of RESTful services that allow developers to earn referral fees”
- walmart.io/apidocs/affiliates/introduction: “Several categories are excluded from the API calls.”
- walmart.io/apidocs/affiliates/affiliate-marketing-api: “Perform text search on the Walmart.com catalogue and get matching items available for sale online.”
- walmart.io/apidocs/affiliates/affiliate-marketing-api: “Get real time item status including price and availability”
- walmart.io/apidocs/affiliates/affiliate-marketing-api: “Your Impact Radius Publisher Id”
- walmart.io/apidocs/affiliates/quickstart: “After the public key is uploaded, consumer id will be created for your application.”