Checkout session API - SixPay Docs

Create checkout session

POST /merchant/tenants/{tenantId}/checkout-sessions
X-Merchant-API-Key: mapi_...
Content-Type: application/json

The Merchant API Key must have the checkout_session:create scope. The endpoint is for a merchant backend; never call it from a browser.

Request fields

Field	Required	Description
`merchantOrderId`	Yes	Stable merchant order identifier.
`items`	Yes	Server-authoritative line items.
`items[].lineItemId`	Yes	Stable line item identifier.
`items[].quantity`	Yes	Ordered quantity.
`items[].unitAmount`	Yes	Decimal string for one unit.
`items[].skuId`	No	Trusted SKU for promotion matching.
`items[].spuId`	No	Trusted product identifier for promotion matching.
`items[].categoryIds`	No	Trusted category identifiers for promotion matching.
`items[].metadata`	No	Product display data; only title, description, and HTTPS image URL reach the browser.
`shippingAmount`	No	Decimal-string shipping charge.
`taxAmount`	No	Decimal-string tax charge.
`otherExcludedChargesAmount`	No	Decimal-string charge excluded from discounts.
`expiresAt`	No	ISO expiration time.

Response

Field	Description
`id`	Checkout session ID passed to SDK UI.
`checkoutToken`	Short-lived bearer credential for this session only.
`expiresAt`	Session expiration time.

Use the returned session credentials with SDK UI. The browser can query only the session’s safe snapshot and promotion operations through X-Checkout-Token.