Init Checkout Transaction

POST /checkout/inittransaction

Initializes a checkout transaction on the legacy checkout flow, returning a transid that is used by the subsequent checkout steps (/checkout/getfinalprice/, /checkout/finalizetransaction/, /checkout/transactionstatus/).

Rate limits

No known rate limit

Request

Authenticated: Yes

Method: POST

Host: checkout.steampowered.com

Path: /checkout/inittransaction

Form Data:

Name	Type	Required	Description
gidShoppingCart	number	Yes	The 64-bit ID of the cart
gidReplayOfTransID	number	No	The 64-bit ID of a previous transaction to replay (-1 if none)
bUseAccountCart	number	No	When 1, uses the account cart instead of the legacy cart
PaymentMethod	string	Yes	The payment method (e.g. visa, paypal, steamaccount)
abortPendingTransactions	number	No	When 1, cancels any pending transactions
bHasCardInfo	number	No	When 1, the request includes credit card information
CardNumber	string	No	The credit card number (only for credit-card payment methods)
CardExpirationYear	number	No	The 4-digit credit card expiration year
CardExpirationMonth	number	No	The credit card expiration month
FirstName	string	No	The billing first name
LastName	string	No	The billing last name
Address	string	No	The billing street address
AddressTwo	string	No	The billing address line 2
Country	string	Yes	The country code of the billing address
City	string	No	The billing city
State	string	No	The billing state/province
PostalCode	string	No	The billing postal code
Phone	string	No	The billing phone number
ShippingFirstName	string	No	The shipping first name
ShippingLastName	string	No	The shipping last name
ShippingAddress	string	No	The shipping street address
ShippingAddressTwo	string	No	The shipping address line 2
ShippingCountry	string	No	The country code of the shipping address
ShippingCity	string	No	The shipping city
ShippingState	string	No	The shipping state/province
ShippingPostalCode	string	No	The shipping postal code
ShippingPhone	string	No	The shipping phone number
bIsGift	number	No	When 1, the purchase is a gift
GifteeAccountID	number	No	The account ID of the gift recipient
GifteeEmail	string	No	The email address of the gift recipient
GifteeName	string	No	The name of the gift recipient
GiftMessage	string	No	The gift message
Sentiment	string	No	The gift sentiment
Signature	string	No	The gift signature
ScheduledSendOnDate	number	No	Unix timestamp when the scheduled gift is sent
BankAccount	string	No	The bank account number
BankCode	string	No	The bank code
BankIBAN	string	No	The IBAN
BankBIC	string	No	The bank BIC/SWIFT code
TPBankID	string	No	The bank ID (e.g. for iDEAL bank selection)
BankAccountID	string	No	The bank account ID
bSaveBillingAddress	number	No	When 1, saves the billing address to the account
gidPaymentID	number	No	The 64-bit ID of the stored payment method
bUseRemainingSteamAccount	number	No	When 1, uses the remaining Steam Wallet balance
bPreAuthOnly	number	No	When 1, performs a pre-authorization only (update billing info)
sessionid	string	Yes	The value of the sessionid cookie

Response

200 OK

Name	Type	Description
success	number	Whether the request was successful (1 on success)
transid	number	The ID of the checkout transaction, used by the subsequent checkout requests
purchaseresultdetail	number	The numeric error detail code (0 on success)
paymentmethod	number	The numeric payment method
palpaltoken	string	The PayPal token, set when the payment method is PayPal (checkout.js reads this as paypaltoken)
specificerrortext	string	The specific error message (only on failure)

Example

POST https://checkout.steampowered.com/checkout/inittransaction { sessionid: "a0b1c2d3e4f5g6h7i8j9klmn" }

{
    "success": 2,
    "purchaseresultdetail": 0,
    "paymentmethod": 0,
    "palpaltoken": null,
    "transid": null
}

The example response was captured from an incomplete probe (empty form body, required fields omitted). No transaction was started.