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Every order is placed on a real account at the retailer. By default that’s Zinc’s problem, not yours: we buy the item on accounts we run and maintain, and your wallet covers the cost. If you’d rather have orders placed on your own retailer account — to keep your card, your loyalty program, or your purchase history in the loop — bring your own account instead.

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The two models

The API fee is $1 per order by default. See Wallet for funding and fees.

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Zinc buys (default)

Send an order with no retailer_credentials_id and there’s nothing to set up. Zinc picks how to check out based on the retailer:
  • Guest checkout, where the retailer allows it — a fresh checkout per order, no standing account involved.
  • A Zinc account, where the retailer requires a login.
Either way Zinc pays the retailer, and your wallet is charged the item cost plus the API fee once the order is placed. Your wallet needs to cover max_price + the fee at order time, or the order fails with insufficient_funds. Keeping those accounts alive — logins, verification challenges, lockouts — is our problem.

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Bring your own account

Two steps, and the second one is not optional:
1

Save the credentials

POST /managed-accounts with the retailer login, and the TOTP secret if the account has 2FA enabled. See Retailer Credentials for the full setup, including email and SMS forwarding for verification codes.
2

Pass the account on each order

Send the account’s short_id as retailer_credentials_id on the order.
Saving a managed account does not by itself change how orders are placed. An order without retailer_credentials_id runs on Zinc’s accounts even when you have your own accounts saved — Zinc never picks one for you. Pass it explicitly on every order that should use your account.
What changes once you do:
  • Zinc signs in as you and checks out with the payment method already saved on that account. No card is sent to the checkout worker.
  • Your wallet is charged the API fee only. The item cost never touches your wallet, because your own payment method paid the retailer directly. You only need the fee on hand to place an order.
  • The account must match the product. A credential saved for one retailer can’t be used on another retailer’s product URL — the order is rejected at creation.
  • One order at a time per account. Orders on the same account queue up and run sequentially, since an account only has one cart. See Order Locking.
  • Account health is yours. Verification challenges land in your inbox or on your phone, so set up email and SMS forwarding, or orders will stall waiting on a code.

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Which should you use?

Default to letting Zinc buy — it’s less to run, and account problems stop being yours. Bring your own account when the purchase has to happen on a specific account: your own card or credit line, a loyalty or cashback program, business pricing, tax-exempt status, or a purchase history you need to keep in one place. You can mix the two. The choice is per order, not per account.