Shopify now supports a UCP permalink route at /buy. One link can add items to a cart, prefill checkout details and send the buyer to checkout, in the same format on any shop that supports UCP. Shopify announced it in a developer changelog post dated October 28, 2026.

For a merchant, this is the simplest handoff an agent has: it needs no authentication and no cart session, only a link.

What changed

Per the changelog, Shopify storefronts support the dev.ucp.shopping.permalink capability starting with UCP version 2026-08-25.

  • Shops list the capability in their UCP discovery profile at /.well-known/ucp. Its config.endpoint points to the shop’s /buy route.
  • Items go in the path as token:quantity pairs. Other fields are query parameters named by their UCP field path, such as buyer/email or discounts/codes/0.
  • Shopify says existing integrations keep working without changes.

What a /buy link can do

The changelog lists these abilities:

  • Add one or more items by variant ID.
  • Prefill buyer details, such as email address.
  • Set the buyer’s country and language.
  • Apply discount codes.
  • Indicate a preference for Shop Pay.
  • Send the buyer to a specific page with a continue_to parameter.

If a link can’t be applied, Shopify redirects the buyer to the continue_to destination if present, or to the storefront. It does not show an error page.

What it does not do yet

Shopify states that /buy doesn’t support selling plans, line item properties, cart notes or cart attributes yet. Stores that depend on subscriptions or product customization fields should keep using /cart links for those cases.

Existing /cart permalinks keep working. Shopify calls them the legacy format and says new capabilities go to /buy.

What to check on your store

  • Your discovery profile. Open /.well-known/ucp on your domain and look for dev.ucp.shopping.permalink. Shopify says shops now list it there.
  • Variant IDs. Links address items by variant ID, so a product whose variants are ambiguous or missing from your data makes a prefilled link harder to build correctly.
  • Your unsupported features. If your best sellers use subscriptions or custom line item properties, an agent cannot prefill those through /buy.
  • Your checkout. The link ends at your checkout page. Shopify’s carts and checkout docs say that for purchases needing escalation or review, the agent redirects the buyer to the merchant’s prefilled checkout, and the merchant remains merchant of record.

Agents are told to read config.endpoint from the discovery profile rather than build the /buy URL themselves. Shopify also warns against putting payment credentials or access tokens in a link, and against sharing links that contain buyer personal details.

FAQ

What is the Shopify /buy permalink?

It is a link format on Shopify storefronts, introduced under UCP 2026-08-25, that adds items to a cart, prefills checkout fields and takes the buyer to checkout. The same format works on any shop that supports UCP.

Do I need to change my Shopify store to support /buy?

Shopify’s changelog says shops now list the permalink capability in their UCP discovery profile and that existing integrations need no changes. The changelog does not describe a merchant setting for it, so check your own /.well-known/ucp file to confirm it appears.

Do /cart links stop working?

No. Shopify says /cart permalinks keep working and are supported, but are now the legacy format. New capabilities go to /buy, and /cart remains the option for selling plans, line item properties, cart notes and cart attributes.

Sources

Related: Is my Shopify store ready for AI agents? covers the wider set of Shopify settings an agent depends on.

A permalink only hands the buyer to your checkout, so whether the purchase completes still depends on the page it lands on, which is the transaction AgentReady audits.