> ## Documentation Index > Fetch the complete documentation index at: https://docs.commercepay.asia/llms.txt > Use this file to discover all available pages before exploring further. # Hosted Session Checkout > Payment gateway hosted session checkout. The following input parameters are expected to be provided by the merchant to initiate a hosted checkout session. Unlike [Direct Integration](/api-reference/direct-integration-api-request-payment), this endpoint does not take a `channelId` — the customer selects their own payment method on CommercePay's hosted payment page. ## OpenAPI ````yaml /openapi.json post /api/services/app/PaymentGateway/InitialSession openapi: 3.0.1 info: title: CommercePay API version: v1 description: > --- **Credentials Accounts** Every account is provided with separate keys for testing and for running live transactions. Once the merchant application has been approved, developers can begin the process of integrating the CommercePay API. The following details will be provided to get started with the integration. Get Started contact: {} servers: - description: Staging url: https://staging-payments.commerce.asia - url: https://payments.commerce.asia description: Production security: [] paths: /api/services/app/PaymentGateway/InitialSession: post: tags: - PaymentGateway summary: Hosted Session Checkout description: "Payment gateway hosted session checkout.\r\n\r\nThe following input parameters are expected to be provided by the merchant to initiate a hosted checkout session. Unlike [Direct Integration](/api-reference/direct-integration-api-request-payment), this endpoint does not take a `channelId` — the customer selects their own payment method on CommercePay's hosted payment page." operationId: post-api-services-app-PaymentGateway-InitialSession parameters: - $ref: '#/components/parameters/AbpTenantId' - $ref: '#/components/parameters/Authorization' - $ref: '#/components/parameters/CapSignature' requestBody: content: application/json: schema: $ref: '#/components/schemas/PaymentSessionInputDto' examples: {} responses: '200': description: Success content: application/json: schema: $ref: '#/components/schemas/PaymentSessionOutputDto' examples: Example 1: value: redirectionType: 1 redirectUrl: string sessionNumber: string '400': description: "Bad Request: \r\nInvalid Timestamp.\r\nInvalid Signature." components: parameters: AbpTenantId: schema: type: string in: header name: Abp-TenantId required: true description: Your unique Merchant ID assigned by CommercePay. Authorization: schema: type: string in: header name: Authorization required: true description: Your API credentials used for authentication (typically a Bearer token). CapSignature: schema: type: string in: header name: cap-signature required: true description: >- A unique security hash used to verify the integrity of the request body. See [Generate Signature](/docs/generate-signature) for how to generate this. schemas: PaymentSessionInputDto: title: PaymentSessionInputDto type: object x-examples: Example 1: currencyCode: MYR amount: 100 referenceCode: string description: Order details ipAddress: string userAgent: string returnUrl: https://returnurl.com/ callbackUrl: https://callback.com/ Customer: email: email@gmail.com mobileNo: '0123456789' name: name username: username identificationNumber: string identificationType: 1 SubMerchant: uniqueId: string name: string PlatformCharge: partnerId: string amount: 0 virtualAccountCode: string RequestPaymentExtraInfo: channelGroupId: 0 hiddenChannel: - 0 expiredInMinutes: 15 tenantId: 0 timestamp: 1621851652617 required: - currencyCode - amount - referenceCode - ipAddress - returnUrl - timestamp properties: currencyCode: type: string description: Currency code with a 3-letter ISO 4217 standard code maxLength: 3 example: MYR amount: type: integer format: int64 description: "Please take note: The Amount parameter only accepts integer units. For example, 1000 is equivalent to 10.00 for the backend.\r\n\r\nInvalid Format: 1,000.00" example: 100 referenceCode: type: string description: Merchant Reference Code maxLength: 50 description: type: string description: Transaction Description example: Order details maxLength: 100 nullable: true ipAddress: type: string description: Customer’s IP address captured by the merchant system maxLength: 50 userAgent: type: string description: >- **[Conditional]** Customer’s user agent. It is recommended to input for a better user experience for specific channels due to different platforms such as desktop, mobile, or app view. Example channels impact: ShopeePay maxLength: 200 nullable: true returnUrl: type: string description: >- Return URL supplied by the merchant server for the payment response and used by CommercePay to redirect the customer's browser back to the desired page on the Merchant’s site example: https://returnurl.com/ maxLength: 500 callbackUrl: type: string example: https://callback.com/ maxLength: 500 description: >- Callback URL is host-to-host communication. CommercePay sends the transaction response to the merchant callback server based on the callback URL given. If the URL is provided, the callback will be triggered; otherwise, it would not trigger. Refer to the Merchant Callback URL to know more nullable: true Customer: $ref: '#/components/schemas/UserInfoDto' SubMerchant: $ref: '#/components/schemas/SubMerchant' PlatformCharge: $ref: '#/components/schemas/PlatformChargeDto' virtualAccountCode: type: string maxLength: 30 description: Code to identify virtual account to make payment. nullable: true RequestPaymentExtraInfo: $ref: '#/components/schemas/RequestPaymentExtraInfo' expiredInMinutes: type: integer description: Set the session expired in minutes example: 30 nullable: true tenantId: type: integer description: Fill in tenant id nullable: true timestamp: type: integer format: int64 description: new Date().getTime() example: 1621851652617 PaymentSessionOutputDto: title: PaymentSessionOutputDto type: object properties: redirectionType: $ref: '#/components/schemas/RedirectionType' redirectUrl: type: string description: URL used for the customer to redirect to the payment page nullable: true sessionNumber: type: string description: Unique CAP Session Number nullable: true UserInfoDto: type: object additionalProperties: false properties: email: type: string description: Customer’s Email Address example: email@gmail.com maxLength: 150 nullable: true mobileNo: type: string description: Customer’s Mobile Number example: '0123456789' maxLength: 16 nullable: true name: type: string description: Customer’s Name example: name maxLength: 36 nullable: true username: type: string description: Customer’s unique ID for recurring payments or next saved payments example: username maxLength: 36 nullable: true identificationNumber: type: string description: '**[Conditional for FPX Recurring]**' nullable: true identificationType: $ref: '#/components/schemas/IdentificationType' SubMerchant: type: object properties: uniqueId: type: string nullable: true name: type: string nullable: true additionalProperties: false PlatformChargeDto: type: object additionalProperties: false description: >- Optional: Only Authorized Partners by CommercePay are allowed to charge platform fees to the merchant properties: partnerId: type: string description: Unique Id to identify authorized partner. nullable: true amount: type: integer format: int64 description: Platform charge amount. nullable: true RequestPaymentExtraInfo: type: object description: '[Optional]' properties: ChannelGroupId: type: integer description: >- Optional: Used for displaying selected channel groups on CommercePay hosted payment web format: int32 nullable: true HiddenChannel: type: array description: 'Optional: To hide channels on CommercePay hosted payment web' deprecated: true nullable: true items: type: integer format: int32 default: 0 WhitelistChannelGroup: type: array description: >- Optional: Specific channel group channel display on the CommercePay hosted payment page. nullable: true items: type: integer format: int32 WhitelistChannel: type: array description: >- Optional: Specific channel display on the CommercePay hosted payment page. nullable: true items: type: integer format: int32 RedirectionType: enum: - 1 - 2 type: integer format: int32 x-enumNames: - UrlRedirection - RenderScriptRedirection description: | Notes: 1 = UrlRedirection IdentificationType: enum: - 1 - 2 - 3 - 4 - 5 type: integer x-enumNames: - NewIdentityNumber - OldIdentityNumber - PassportNumber - BusinessRegistration - Others x-examples: {} description: >- **[Conditional for FPX Recurring]** New Identity Number = 1, Old Identity Number = 2, Passport Number = 3, Business Registration = 4, Others = 5 ````