Payments With Preauthorization

Process a payment with preauthorization via the KVELL payment page.

Difference from the standard payment page: the card data entry form opens immediately, without a payment method selection step. The card is not saved.

Processing a payment

URL

Method: GET or POST

• Production: https://pay.kvell.group/checkout/preauthorize
• Stage: https://pay.stage.kvell.group/checkout/preauthorize

Request parameters

Name	Type	Required	Description
api_key	string	Yes	Unique shop identifier
signature	string	Yes	Signature
amount	integer	Yes	Amount in kopecks
description	string	Yes	Transaction description
transaction	string	Yes	Unique transaction number on the merchant's side
success_url	string	Yes	URL to redirect to on successful completion of the request
fail_url	string	Yes	URL to redirect to on failed completion of the request
auto_return	string	No	Automatic redirect to success_url or fail_url after payment. Specified in seconds. If the value is greater than 0, the redirect happens after N seconds. If the value is 0, the redirect happens immediately.
expires_at	integer	No	Payment expiration date and time as a UNIX timestamp in seconds
extra_data	json	No	Additional information
fiscal_data	json	No	Receipt fiscalization under 54-FZ
split_data	array	No	Payment splitting

Building the signature

The signature is built by concatenating api_key, transaction, amount, and secret_key. A sha256 hash is computed from the resulting string:

sha256({api_key}{transaction}{amount}{secret_key})

If the expires_at parameter is passed, it is included in the signature.

sha256({api_key}{transaction}{amount}{expires_at}{secret_key})

where secret_key is the secret key found in the merchant's shop settings.

Request examples

GET request

https://pay.kvell.group/checkout/preauthorize?api_key={api_key}&signature={signature}&amount={amount}&description={description}&transaction={transaction}&success_url={success_url}&fail_url={fail_url}&auto_return={auto_return}&extra_data={extra_data}&fiscal_data={fiscal_data}&split_data={split_data}

POST request

<form action="https://pay.kvell.group/checkout/preauthorize" method="POST">
    <input type="hidden" name="api_key" value="3a8c82d6-d2c6-4165-9a6b-ab3f14d965ae">
    <input type="hidden" name="amount" value="10000">
    <input type="hidden" name="description" value="Product #1">
    <input type="hidden" name="signature" value="afc09ed74d83849d44c1f1906b10d20c147bf0eb25da940c020c980b3b44ca38">
    <input type="hidden" name="success_url" value="http://yoursite.com/success">
    <input type="hidden" name="fail_url" value="http://yoursite.com/fail">
    <input type="hidden" name="transaction" value="fbfe9f88-d5c7-4994-aed6-ee8003f4f342">
    <input type="submit" value="Pay">
</form>

POST request with JSON

When sending data in JSON format, you must set the Accept: application/json and Content-Type: application/json headers. The response will contain a temporary URL to redirect the user to the payment page.

Example request:

curl -X POST https://pay.kvell.group/checkout/preauthorize \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -d '{
    "api_key": "3a8c82d6-d2c6-4165-9a6b-ab3f14d965ae",
    "amount": 10000,
    "description": "Product #1",
    "signature": "afc09ed74d83849d44c1f1906b10d20c147bf0eb25da940c020c980b3b44ca38",
    "success_url": "http://yoursite.com/success",
    "fail_url": "http://yoursite.com/fail",
    "transaction": "fbfe9f88-d5c7-4994-aed6-ee8003f4f342"
  }'

Example response:

{
  "url": "https://pay.kvell.group/checkout/preauthorize/90afde444c6d15c83289ece14e90b7e2927a3a4e"
}

Callbacks

Callbacks are sent the same way as for a standard payment. See the Callbacks section for details.