# Integration

Merchants want to integrate the payment flow on their cashier page, PayerMax provides Direct API access.

For the Direct API interface, merchants need to have PCI-DSS certification if they process card number information by themselves.

### 1. Integration Steps

The user enters payment information on the checkout page and calls the Direct API interface to complete the payment.

![](https://img-cdn-sg.payermax.com/public/20241024-55895914-2418-4ecc-88f7-652ad550d684.jpg)

### 2. Order Repeat Check

When a merchant submits a Direct API request, the submitted order number must be unique. If PayerMax recognizes that the merchant is requesting with the same order number, it will reject the request and return: Duplicate order.

### 3. Response Scenarios

The transaction status of Direct API access is divided into the following scenarios:  

(1) Complete the payment online, please update the transaction result according to[【Transaction Status】](https://docs.payermax.com/en/202606-version/appendix/collection/transaction-status.md)in the response, and do not update the transaction result according to the code and message.  

(2) Redirect to wallet/bank/3ds authentication, the response contains redirectUrl, please update the transaction result according to[【Callback Notification】](https://docs.payermax.com/en/202606-version/receipt/result-notifications/callback-notification.md) 

### 4. API Parameters

For details, please refer: [API](https://docs.payermax.com/api.html?docName=New%20Version&docVer=v1.0&docLang=en#/paths/aggregate-pay-api-gateway-applyToken/post)