> For the complete documentation index, see [llms.txt](https://apidocs.akinon.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://apidocs.akinon.com/commerce-openapis/checkout/card-payment.md). # Card Payment ## Checkout Card Payment Accept credit and debit card payments through a multi-step flow covering BIN lookup, installment selection, 3D Secure verification, payment confirmation, saved card selection, and order completion. ### Authentication These endpoints support both authenticated and anonymous sessions. * **Authenticated users**: Session cookie (`sessionid`) tracks checkout progress. * **Anonymous users**: Guest checkout is available when the `CAN_GUEST_PURCHASE` setting is enabled. ### Request Format Include the following header in all checkout requests: * **x-requested-with**: `XMLHttpRequest` ### Dynamic Settings The following settings are managed at runtime through the admin interface and do not require a server restart. #### THREE\_D\_SECURE\_ENABLED Master switch for 3D Secure verification. When disabled, 3D Secure is skipped regardless of other rules. #### THREE\_D\_SECURE\_RULES Rule-based conditions that determine when 3D Secure is required. Rules are evaluated in order; the first match triggers 3D Secure. Only active when `THREE_D_SECURE_ENABLED` is enabled. Available rule types: amount threshold, POS terminal identifier, failed attempt limit per email address, failed attempt limit per IP address, guest user status, first-time purchaser, payment currency. #### INSTALLMENT\_FILTERS Filters that restrict which installment options are presented. Filters are applied in sequence; each may remove options or stop further filtering. ### Static Settings The following settings are configured in the server environment and require a restart to take effect. #### DEFAULT\_CARD\_SLUG Fallback card identifier used when a BIN number is submitted but no matching record is found. Defaults to `other`. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://apidocs.akinon.com/commerce-openapis/checkout/card-payment.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.