Overview
How might we let an AI shop across merchants into one cart, so people review and pay once instead of visiting each storefront themselves?
When to use
- Shopping assistants that assemble kits or lists from multiple retailers.
- Builds where compatibility and seller clarity matter (PC parts, appliances, gifts).
- Flows where price watching belongs on the shared basket, not only on each PDP.
- Checkout that places merchant-specific orders from one saved wallet.
When to skip
- Single-SKU flows where instant buy is enough and a multi-merchant cart adds noise.
- Markets where multi-merchant carts violate local commerce or tax rules.
- Products that cannot show clear merchant of record or return ownership per line item.
States
Design the cart as the place AI shopping intent becomes a reviewable, multi-merchant order plan.
- 01
Sourcing
The assistant finds items across merchants for the user’s goal and proposes a basket.
- 02
Adding
Accepted items enter one cart. Every line keeps retailer attribution.
- 03
Watching
The cart monitors price, stock, and fit across merchants while the shopper reviews.
- 04
Insight
Proactive notices surface drops, restocks, or incompatibilities before pay.
- 05
Reviewing
The cart groups by merchant with clear subtotals. Shoppers can edit or remove lines.
- 06
Paying
One wallet pay places the merchant orders. Explicit consent still gates spend.
- 07
Confirmed
Separate confirmation IDs per merchant. Each brand remains merchant of record for its lines.
Key UX elements
The parts that must be present when AI shops across merchants into one cart.
Source
Let AI pull from multiple merchants.
The assistant finds candidates across retailers for one shopping goal, instead of sending the user store-hopping.
Cart
Keep one reviewable basket.
Accepted items land in a single cart the user can edit before any money moves.
Seller
Show who fulfills each line.
Group by merchant so returns, shipping, and support ownership stay clear.
Insight
Make the cart proactive.
Price drops, stock, and compatibility across items appear before pay.
Pay
Place merchant orders from one wallet.
One pay action charges the saved wallet and creates separate merchant orders with clear totals.
Receipt
Confirm per merchant.
Show confirmation IDs, sellers, and line totals so dual orders do not feel like one opaque charge.
Rules
Hiding which retailer fulfills each line so returns and support are unclear.
Silent price or availability changes at pay time with no notice.
Charging once without showing that separate merchant orders will be placed.
Forcing users back to each storefront to finish what the AI already assembled.
Evidence
| Product | Implementation |
|---|---|
| Google Universal Cart | AI-assisted shopping cart that holds items from multiple retailers and monitors deals and fit before checkout. |
| Google Shopping / UCP | Checkout that can pay with a saved wallet while each brand stays merchant of record for its lines. |
| Gemini | Chat finds products across sellers and adds them into one reviewable cart before pay. |
| Perplexity Shopping | Research and buy paths that compare merchants, then stage purchase without sending users store-hopping. |