Shopify storefronts now support the UCP dev.ucp.shopping.permalink capability starting with UCP 2026-08-25 on a new /buy route. You can use a single /buy link to add items to a cart, prefill checkout details, and take the buyer to checkout, using the same link format on any shop that supports UCP. You don’t need to change existing integrations to keep them working.
What changed
Shops now list the dev.ucp.shopping.permalink capability in their UCP discovery profile at , and its config.endpoint points to the shop’s /buy route.
A /buy link encodes items in the path as token:quantity pairs and sets other cart and checkout fields with query parameters named by their UCP field path, such as or .
With a /buy link, you can:
- 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 on the shop with a
parameter
If a link can’t be applied, Shopify redirects the buyer to the destination when it’s present, or to the shop’s storefront instead of showing an error page.
Existing /cart permalinks keep working, although they’re now the legacy format. Shopify keeps supporting them, but new capabilities go to /buy. /buy doesn’t support selling plans, line item properties, cart notes, or cart attributes yet, so you should keep using /cart if you need those features.
What to do
Use /buy for new links, and move existing /cart links to /buy where you can. New capabilities only apply to /buy, and the same link format works on any business that supports UCP. Your /cart links keep working, so you can migrate on your own schedule. If you rely on selling plans, line item properties, cart notes, or cart attributes, keep using /cart for now.
Permalinks don’t use capability negotiation, so you don’t need to declare dev.ucp.shopping.permalink in your agent profile. To build a link, read config.endpoint from the shop’s discovery profile instead of constructing the /buy URL yourself.
Never put payment credentials or access tokens in a link, and avoid buyer personal details in links you share widely.