MIT Payment Integration Guide

Before integrating, please review the API Description and Common Rules and CIT vs. MIT Transaction Modes.

MIT (Merchant-Initiated Transaction) allows your server to initiate subsequent off-session charges using a stored payment credential (tokenID) after the cardholder completes an initial on-session (CIT) payment and authorization. It is ideal for usage-based billing, auto top-ups, installments, and merchant-scheduled recurring billing.

If you offer fixed-amount, fixed-cycle plans with a defined term, we recommend using HaiPay’s managed Subscription Payment (/subscription/apply), where HaiPay schedules recurring charges automatically.
When using Component Mode for MIT, always set mode: 'payment' (MIT is categorized as standard collection on HaiPay; 'subscription' is only for fixed-term subscriptions).

Two-Phase Integration Flow

Phase 1: Initial Transaction (On-Session Authorization & First Charge to Obtain tokenID)

Your backend calls MIT Collection Apply POST /usd/mit/apply without passing tokenID.
Use the returned payUrl (Checkout Mode) or clientToken (Component Mode with mode: 'payment') so the shopper completes the first payment and authentication on-session.
Upon payment success, HaiPay sends an asynchronous webhook to notifyUrl containing the tokenID bound to the user and card. Securely store the mapping between tokenID and partnerUserId.

Phase 2: Subsequent Transactions (Off-Session Merchant-Initiated Charges)

Whenever a charge condition is met, your backend calls POST /usd/mit/apply again, passing the stored tokenID (along with the same partnerUserId).
HaiPay validates the tokenID, executes the off-session charge directly, and notifies your notifyUrl asynchronously (you can also query status via /usd/collect/query).

MIT-Specific Parameters

In addition to standard collection parameters, /usd/mit/apply includes the following fields:

Parameter	Required	Type	Description
`tokenID`	No	String	Stored credential token: • Initial transaction (Phase 1): Omit this field; obtain `tokenID` from the payment webhook after success. • Subsequent charge (Phase 2): Required to charge the previously authorized card or wallet.
`loadingType`	No	Integer	Result page display control: • `0` (default): Display the standard payment result view. • `1`: Display a loading spinner only without order details.
`inBankCode` / `paymentMethods`	Mutually Exclusive	String	When `inBankCode` is omitted, `paymentMethods` is required, and vice versa. Pass `paymentMethods` (e.g., `"GOOGLE_PAY,CREDIT_CARD"`) to dynamically control displayed payment methods and their top-to-bottom order.

Request Examples (`POST /usd/mit/apply`)

Phase 1: Initial Card-Saving Charge (omit tokenID)
Phase 2: Subsequent Off-Session Charge (pass tokenID)

{
  "appId": 1054,
  "orderId": "MIT_INIT_20261110001",
  "amount": "19.99",
  "phone": "+12025551234",
  "email": "robert.taylor@gmail.com",
  "name": "Robert Taylor",
  "payType": "BANK_TRANSFER",
  "inBankCode": "CREDIT_CARD",
  "callBackUrl": "https://merchant.com/payment/success",
  "callBackFailUrl": "https://merchant.com/payment/fail",
  "cancelUrl": "https://merchant.com/payment/cancel",
  "notifyUrl": "https://merchant.com/api/notify",
  "subject": "Initial card authorization & payment",
  "partnerUserId": "149597870",
  "sign": "af0gAHkUOyYHu9owQp8NJ4mPEeUW4vuJcjdxqLIzrVw8AvpLSjD1DXupReSG..."
}

{
  "appId": 1054,
  "orderId": "MIT_SUBSEQ_20261210001",
  "amount": "29.99",
  "phone": "+12025551234",
  "email": "robert.taylor@gmail.com",
  "name": "Robert Taylor",
  "payType": "BANK_TRANSFER",
  "inBankCode": "CREDIT_CARD",
  "tokenID": "tok_abc123def456",
  "loadingType": 0,
  "callBackUrl": "https://merchant.com/payment/success",
  "callBackFailUrl": "https://merchant.com/payment/fail",
  "notifyUrl": "https://merchant.com/api/notify",
  "subject": "Auto top-up / renewal charge",
  "partnerUserId": "149597870",
  "sign": "af0gAHkUOyYHu9owQp8NJ4mPEeUW4vuJcjdxqLIzrVw8AvpLSjD1DXupReSG..."
}

Payment Types, Codes & Limits

Single-transaction limits for MIT are 0.99 – 1000 USD:

Currency	Payment Type (`payType`)	Payment Code (`inBankCode`)	Single Limit (USD)	Status	Card Network / Wallet
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	`BANK_TRANSFER`	`CREDIT_CARD`	0.99 - 1000	Available	American Express (AMEX)
USD	`BANK_TRANSFER`	`CREDIT_CARD`	0.99 - 1000	Available	Diners Club (DINERS)
USD	`BANK_TRANSFER`	`CREDIT_CARD`	0.99 - 1000	Available	Discover (DISCOVER)
USD	`EWALLET`	`GOOGLE_PAY`	0.99 - 1000	Available	Google Pay
USD	`EWALLET`	`APPLE_PAY`	0.99 - 1000	Available	Apple Pay

Mutual Exclusivity between inBankCode and paymentMethods:

Pass inBankCode when specifying a single payment method (leave paymentMethods empty).
Pass paymentMethods (comma-separated, e.g., "GOOGLE_PAY,CREDIT_CARD") to dynamically control which payment methods are displayed and their top-to-bottom display order (leave inBankCode empty). For example, passing "GOOGLE_PAY,CREDIT_CARD" displays only Google Pay followed by Credit Card from top to bottom.
This dynamic display and ordering capability also maps to the Global Cashier.

Core API Reference

For full field specifications, response schemas, and live debugging, visit the API Reference:

MIT Collection Apply

POST /usd/mit/apply — Initiate initial authorization or subsequent off-session charges.

Collection Order Query

POST /usd/collect/query — Query the final status of an MIT order.

Refund Apply & Query

POST /usd/refund/apply — Issue full or partial refunds for completed MIT charges.

Quick start

Merchant Guide

Common Payment

Global Payment

Unified API

End To End Testing

Appendix

Merchant FAQ

MIT Payment Integration Guide

Two-Phase Integration Flow

MIT-Specific Parameters

Request Examples (`POST /usd/mit/apply`)

Payment Types, Codes & Limits

Core API Reference

MIT Collection Apply

Collection Order Query

Refund Apply & Query

​Two-Phase Integration Flow

​MIT-Specific Parameters

​Request Examples (POST /usd/mit/apply)

​Payment Types, Codes & Limits

​Core API Reference

MIT Collection Apply

Collection Order Query

Refund Apply & Query

​Related Topics

Two-Phase Integration Flow

MIT-Specific Parameters

Request Examples (`POST /usd/mit/apply`)

Payment Types, Codes & Limits

Core API Reference

Related Topics