> ## Documentation Index > Fetch the complete documentation index at: https://doc.haipay.net/llms.txt > Use this file to discover all available pages before exploring further. # MIT > Understand HaiPay MIT (Merchant Initiated Transaction) mode, including flowchart, collection API, query and refund endpoints. **Before reading this API documentation, be sure to review the [API Description Guide](/docs/en/guide/api_description_guide)** Use [Payment Link](/docs/en/V20260628/api/version2/payment-link) or [Front-End Component](/docs/en/V20260628/api/version2/frontend-payment-element) to quickly integrate MIT payment. ## MIT Mode Overview **MIT (Merchant Initiated Transaction)** After a user completes a one-time payment authorization, the merchant can initiate charges without the user being present. This mode is widely used for **subscription billing, installment payments, membership renewals, and deferred charges**. ### Basic Flow 1. **User Authorization** * The user enters payment information during the first transaction and completes the required authentication. * The merchant stores the user's payment credentials (`tokenID`) for subsequent charge requests. 2. **Merchant Initiates Charge** * The merchant directly initiates a charge request using the stored credentials based on the agreed schedule or conditions. * Since the transaction is an **off-session** scenario (the user does not participate), the system processes it based on user authorization and compliance requirements. 3. **Authentication Requirements** * In most cases, the transaction completes directly. * If the issuing bank or risk control system requires re-verification, the transaction may enter a pending state that requires the user to provide additional verification. ### Key Features * **Better UX**: Users do not need to manually enter payment information each time. * **Compliant & Secure**: Meets international payment regulations and Strong Customer Authentication (SCA) requirements. * **Wide Application**: Suitable for subscription billing, auto-renewal, installment deductions, and deferred settlement. ## MIT Flowchart ```mermaid theme={null} flowchart TD A[User: places order on merchant platform] --> B{Transaction type check} N[Payment callback] O[Merchant: deliver service/goods] P[Merchant: notify user of Payment Failed] subgraph S2 [Scenario 2: subsequent transaction] direction TB I[Subsequent] --> J[Merchant: sends transaction
request with token to Haipay] J --> K{HaiPay: Verify token} K -->|Valid| L[HaiPay: Execute auto-charge] L --> N K -->|Invalid/Failed| M[Payment Failed] M --> P end subgraph S1 [Scenario 1: first transaction] direction TB C[First transaction] --> D[HaiPay: provide Payment URL] D --> E[User: confirm payment] E --> F[Payment Success] F --> G[HaiPay: Generate secure token
(bind user & merchant)] G --> N N --> O end B --> C B --> I ``` ## Transaction Limits | Transaction Type | Limit (USD) | | :--------------- | ----------- | | Collection | 0.99-1000 | ## MIT Payment API ### Collection Apply **Description:** * Create a MIT mode collection order **URL:** USD: `/usd/mit/apply` Description: Use the appId corresponding to USD. After successful payment, the user's USD balance increases. **Parameters:** | Parameter | Required | Type | Description | | :-------------- | :------- | :------ | :------------------------------------------------------------------------------------------------------------------------------------------ | | appId | Yes | Long | Business ID (obtained from the dashboard; use the one corresponding to the currency in the URL) | | orderId | Yes | String | Merchant order number (must be unique, max 48 characters) | | name | No | String | User name; real name recommended. Format: firstName and lastName separated by space. Example: John Doe | | phone | No | String | Real phone number (format reference: [phone format](/docs/en/guide/frequently_asked_question#phone_format)) | | email | No | String | Real email address | | amount | Yes | String | Transaction amount (2 decimal places; no punctuation such as ",") | | payType | Yes | String | [Payment type](#Payment-methods) | | inBankCode | Yes | String | [Payment code](#Payment-methods) | | clientIp | No | String | Client IP address | | callBackUrl | Yes | String | Redirect URL after successful payment | | callBackFailUrl | Yes | String | Redirect URL after failed payment | | notifyUrl | No | String | Callback URL | | subject | Yes | String | Payment remark | | body | No | String | Remark details | | partnerUserId | Yes | String | Unique user identifier (e.g. userId) for risk control. Must be real and valid. Format: digits, letters, or common symbols -\~!@#\$%&\*()\_. | | tokenID | No | String | Payment token. Not required for the first transaction; required for subsequent charges. Obtained via callback. | | loadingType | No | Integer | 0 (default) – Show normal payment result page; 1 – Show loading animation, hide order info. | | cancelUrl | No | String | Cancel URL; if provided, user can click to return from payment page | | sign | Yes | String | Signature | **Request Example** ```json theme={null} { "appId": 1054, "orderId": "M233323000059", "amount": "300", "phone": "09230219312", "email": "23423@qq.com", "name": "test", "inBankCode": "USA", "payType": "BANK_TRANSFER", "partnerUserId": "149597870", "sign": "af0gAHkUOyYHu9owQp8NJ4mPEeUW4vuJcjdxqLIzrVw8AvpLSjD1DXupReSG/CyuSkFRyiIvCp5u703AuGGmfgD2gKDH3Ywau41bAbG2jnHJ8mtjiSJ5iWUzanyd4Kr7d1+rETbzUl7/BkW3t0X8UUFdqpxwG8DPUjAwUKfplWDHV7koG51Ozexd80DCsmW6eWdouAZ1uNXGLYmV3ftE3BmfNRtuv1C5bfTJWrTEIOxbF6g2uYOFZTlIgrQgd7/2PsAYwQQXNz8Q8CYl4OxqCv4pXJxaLWPbR5tqZu9og5kn32C9aHW/NlU1y39vzz+4ef81yPAqUV9oHlSMSPrMmw==" } ``` **Response Example** ```json theme={null} { "status": "1", "error": "00000000", "msg": "", "data": { "orderId": "M233323000059", "orderNo": "6023071013539074", "payUrl": "", "clientToken": "", "sign": "YEoA8Y2JzQFGVzwJSqmemm1Kfv/bfyIfCqv2dp7RNzT5B72AQvdD+nt2nR4sL1HWscvmNHyVt5ovAi7MMhy3ziih/sMph+wPx4YjH3W1h5DyBvSlWvaKfKrK5ViomZ0pPYWydwRHnnRnicxToHK9S6qtSy7Q73O0hdz4hJ9p41Th3ycBl2Q9SeqSZYSY1ohcPDhdyRf2y0prb8rHgpBKzxZ5BKX/1bsE9OmsSEHAEYT8OGgko6aNe8XPAhr4G48cpWTftvnGQuzh0O65nuZRI/PF+Axt2zJCVbFHDDSREI9NlAT82ebDqhlVdxQzKE67D1nxgjb3dPmDUYHOBpmwxQ==" } } ``` Response data parameters | Parameter | Type | Description | | :---------- | :----- | :------------------------------------------------------------------------------------------------------------------------------------ | | orderId | String | Merchant order number (must be unique) | | orderNo | String | Platform order number | | payUrl | String | Payment URL | | clientToken | String | Client token for use in the Front-End Component (see [Front-End Component](/docs/en/V20260628/api/version2/frontend-payment-element)) | | sign | String | Signature | ### Collection Query **Description:** * Query a collection order **URL:** USD: `/usd/collect/query` **Parameters:** | Parameter | Required | Type | Description | | :-------- | :------- | :----- | :---------------------------------------------------------------------------------------------- | | appId | Yes | Long | Business ID (obtained from the dashboard; use the one corresponding to the currency in the URL) | | orderId | Yes | String | Merchant order number | | orderNo | No | String | Platform order number (faster response) | | sign | Yes | String | Signature | **Request Example** ```json theme={null} { "appId": 1054, "orderId": "M22222000028", "sign": "EmyJGm3ELzG4FsOd0Krs9ncbSjo4oTGuXWML+7djYla3+VAwd9wS17z38p/7U2ZAjroO04XrE7YXcB1o76Dtyipj3h3bJzs7FYma1QNkMUdt9hh7m8U6hMsMQX7vIWHtXNwz4pbTSC75+kQWXaCew7KoE6LXECdJU8AISgNgeki2TK9R0pCfshr0Z2SZBPeuT6OvIH5LdmqgdZhuqnffGU2qnXk4KMkO848e6/WALLBR+LE1wyKHfPnYVcuKSMVYxkvKyyIL5JIPEgW0o5bh4RCbaUn3NZtyYwrU1uQ3ZDFRThm9j6XAQP+LBlmq3nOePqBtp/VDVarRaV+7FbQg3A==" } ``` **Response Example** ```json theme={null} { "status": "1", "error": "00000000", "msg": "", "data": { "orderId": "M22222000028", "orderNo": "6023042811314347", "amount": "50.00", "actualAmount": "0.00", "fee": "0.00", "status": 1, "sign": "fP433ygWVDLVGxYkVnIJj7riGq0U3vyVX+MbBAImxfGLZkZcEAHVEoVYuULZSmXAAXKRSyd67WlDNm+24pougM54ofAoH4HMtCL2tfCoBReFyz3z02AGKkrKE2xWhSpWoqfQoBvzwuN5iGMMu0s9Q1YvqiwJ8WDVIENnmiIyD8qDJN7caHTW2US14/faG+69AvnuIgJ/nu7/jogOlgEYdZdVYU7gcRDE+d47KjlFGswQkJ/h/uzV7cWtUqrtOO7ZnZ3/z33Xx8awokX36QoYcPSWAU0h+Ij9O9402HNhm1eTbYcLU0uI/z8xCAtyAI/tTyiFijpiNlxUKQj+zKsILw==" } } ``` Response data parameters | Parameter | Type | Description | | :----------- | :------ | :------------------------------------------------------------------------------------------------------------ | | orderId | String | Merchant order number (must be unique) | | orderNo | String | Platform order number | | amount | String | Transaction amount | | actualAmount | String | Actual amount received | | fee | String | Fee | | status | Integer | Status (0: not started, 1: paying, 2: success (final), 3: failed (final), -1: exception pending confirmation) | | payTime | String | Payment success time (available when status=2), local time, format: yyyy-MM-dd HH:mm:ss | | errorMsg | String | Payment failure reason (available when status=3) | | sign | String | Signature | ## Refund API ### Refund Apply **Description:** * Initiate a refund for the original credit card transaction. Note that the synchronously returned refund status should be confirmed via the query API. **URL:** USD: `/usd/refund/apply` **Parameters:** | Parameter | Required | Type | Description | | :----------- | :------- | :----- | :---------------------------------------------------------------------------------------------------------- | | appId | Yes | Long | Business ID (obtained from the dashboard; use the one corresponding to the currency in the URL) | | orderId | Yes | String | Merchant refund order number (new merchant order number; cannot reuse the original collection order number) | | orderNo | Yes | String | Platform order number (from the original collection response) | | refundAmount | No | String | Optional; if omitted, full refund is applied | | sign | Yes | String | Signature | Response data parameters | Parameter | Type | Description | | :-------- | :----- | :---------------------------------------------------------------------------------------------------------------------------- | | appId | String | Business ID | | orderNo | String | Platform order number (from the original collection response) | | orderId | String | Merchant refund order number | | refundNo | String | Platform refund number for this request | | status | String | Refund status: 1 = success, 0 = processing, 2 = failed. Normally returns processing initially; use query API to check status. | | errorMsg | String | Error message (may not always be present) | | sign | String | Signature | ### Refund Query **Description:** * Query the result of a refund request. **URL:** USD: `/usd/refund/refundQuery` **Parameters:** | Parameter | Required | Type | Description | | :-------- | :------- | :----- | :---------------------------------------------------------------------------------------------- | | appId | Yes | Long | Business ID (obtained from the dashboard; use the one corresponding to the currency in the URL) | | orderId | No | String | Merchant refund order number | | refundNo | No | String | Platform refund number (returned from refund apply; prefer this field for queries if available) | | sign | Yes | String | Signature | Response data parameters | Parameter | Type | Description | | :----------- | :----- | :------------------------------------------------------------------------------------------- | | appId | String | Business ID | | orderNo | String | Platform order number (from the original collection response) | | orderId | String | Merchant order number | | refundNo | String | Platform refund number | | status | String | Refund status: 1 = success, 0 = processing, 2 = failed. Use this status as the final result. | | errorMsg | String | Error message (may not always be present) | | refundAmount | String | Refund amount | | sign | String | Signature | ## Payment Type and Payment Code | Currency | Payment Type (payType) | Payment Code (inBankCode) | Limit | Status | Description | | :------- | :--------------------- | :------------------------ | :-------- | :-------- | :---------- | | USD | BANK\_TRANSFER | CREDIT\_CARD | 0.99-1000 | Available | VISA | | USD | BANK\_TRANSFER | CREDIT\_CARD | 0.99-1000 | Available | MasterCard | | USD | BANK\_TRANSFER | CREDIT\_CARD | 0.99-1000 | Available | JCB | | USD | EWALLET | GOOGLE\_PAY | 0.99-1000 | Available | Google Pay | | USD | EWALLET | APPLE\_PAY | 0.99-1000 | Available | Apple Pay | ## Test Card Numbers For test card numbers, see [Test Card Numbers](/docs/en/V20260628/api/version2/test-cards), covering successful payments, declines, and dispute scenarios. ## Related Topics * [Front-End Component](/docs/en/V20260628/api/version2/frontend-payment-element) * [Payment Link](/docs/en/V20260628/api/version2/payment-link) * [VISA/MASTER Payment](/docs/en/V20260628/api/version2/creditcard)