# Introduction This guide outlines the payment management API endpoints in the system. These endpoints allow you to retrieve card information with installment options, manage stored credit cards with OTP verification, and integrate with Masterpass payment gateway for secure checkout. The Payments API provides functionality for: **1. Card & Installment Management** * Retrieve available payment cards for basket checkout * Get installment options for pre-orders * View card-specific installment plans for products * Filter cards based on amount and business rules * Calculate interest amounts and installment breakdowns **2. Stored Card Operations** * Verify phone numbers for OTP-based card storage * Send OTP codes for secure card storage authorization * Save credit cards with tokenization support * Multi-gateway support (POS-based card storage) * Secure card token management **3. Masterpass Integration** * Retrieve Masterpass JavaScript configuration * Support for 3D Secure authentication * Dynamic merchant configuration * Client-side integration parameters * Custom merchant type support Each endpoint is designed to support secure payment operations where users can select payment methods, view installment options, and safely store payment cards for future transactions. **NOTE:** * Card list endpoints are public (no authentication required) * Stored card operations require authenticated users * Masterpass JS endpoint is public for client-side integration * All card storage operations use secure tokenization --- # Agent Instructions: 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: ``` GET https://apidocs.akinon.com/commerce-openapis/payments/introduction.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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.