Form fields and customization

The Checkout page is shown to the Customer after a payment initiation.

This is the stage where a customer enters their payment data like cards and personal info.

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This page covers the fields the customer sees on the rendered form. For the full list of parameters you send in the authentication request — organized by operation type (purchase, debit, credit, transfer) with required and optional columns — see Sale (Authentication session).

Fields and Validation

The list of the fields on the Checkout page depends on the request parameters and the specified payment method.

Your customers will not see the fields if the acquirer does not need the information that is transmitted in them. For example, if an alternative payment method is specified, the card data is not displayed on the Checkout page.

As well, pay attention to the conditional fields such as e-mail or billing address. If the e-mail and billing address (data object) parameters are specified in the request, the Checkout page will not contain them.

Additional fields can also be displayed if a payment method is selected that requests additional data from the Customer.

The Checkout page has the fields validation. In case of the invalid data the error message will be shown and the field will be highlighted.

General fields

Validation rules for the fields rendered by Checkout when they are not supplied in the auth request. Any field you provide in the customer or billing_address object is hidden from the customer.

The Error column shows the literal string returned by the platform on validation failure. Display it to the customer as-is, or map it to your own UI copy.

Fields	Type	Limitations	Error
Card number	Integral	Lun algorithm, length 14-19 numbers	Invalid card
Expiry Date	Date	2-2 numbers (in the format mm-yy), after today's date	The expiration date of card is expired and not valid.
Security code	Integral	Up to 4 characters	Invalid security code
Name on card	String	Up to 32 characters	The name on card field Must contain at least 2 words: first name and last name. Allowed special characters: hyphens, apostrophes, diacritics
Country	List	2-letters code	Country is required. Please enter a valid Country
State/Region	String List - for USA, Canada, Australia, Japan, India	2-letter code for US, CA, AU, JP, IN; free string elsewhere	Varies by country
City	String	2-40 characters	City is required. Please enter a valid City
Address line	String	2-255 characters	Address line is required. Please enter a valid Address line
Zip code	String	2-10 characters	Zip code is required. Please enter a valid Zip code
Phone number	String	Up to 32 characters	Phone number is required. Please enter a valid Phone number

iFrame

Embed the Checkout page in an iframe on your domain:

<iframe src="<redirect_url>" height="600" width="300"></iframe>

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The browser hosting your iframe must allow third-party cookie storage for the Checkout origin. Without it, the customer is silently logged out during 3DS or redirect flows and the payment session breaks.

Cross-domain requests against Checkout are blocked by CSP.

Customize your page

Two ways to brand the Checkout page: no-code in the admin panel, and custom payment forms via the SDK.

Use the Checkout SDK for branding to create custom payment forms and obtain a form_id for your authentication requests.

No-code branding

In the admin panel, go to Configuration > Branding to customize colors, logo, and buttons. Settings apply globally to all sessions for that merchant. There is no per-session override.

Custom payment forms

If you maintain a branded custom form, send a form_id in the auth request. Configure forms via the SDK Checkout admin module.

{ "form_id": "27106696-656c-...-7e11ae873370" }