WeChat

Overview

Introduction

WeChat is a payment method which allows you to process payments in Thai bahts by using e-wallets in Thailand. This method supports purchases.

This article provides information about working with the WeChat method: general insights are presented in the Overview section, while information about the actions required to process payments and perform other actions is presented in the sections that follow.

General information

Payment method type QR code payments
Payment instruments digital wallets
Countries and regions TH
Payment currencies THB
Currency conversion on the Eposservice side
One-time purchases +
Credential-on-file purchases –
Full refunds –
Partial refunds –
Payouts –
Chargebacks –
Notes the expiration time of the QR code on the WeChat service side is 2 hours starting from the creation of the code
Onboarding and access fee refer to your Eposservice key account manager

Interaction diagram

Payment processing by using the WeChat method involves the merchant's web service, one of Eposservice interfaces, the Eposservice payment platform, and technical facilities of the WeChat service.



Operations support

Various platform interfaces can be used to process payments and perform operations using the WeChat method. Purchases can be processed by using Payment Page, Gate and Dashboard (using payment links).

The following properties and limitations apply to the WeChat method.

Amounts Times ¹
minimum maximum base threshold
Purchases 1.00 – – 2 hours
Note:
  1. The base and threshold times are defined as follows:
    • The base time is the average estimated time between the moment a payment is initiated in the payment platform to the moment the payment result is sent to the web service. The base time evaluation is made on the assumption of normal operation of all technical facilities and communication channels and typical customer behaviour (if any input from the customer is required). Use the base time to estimate when to react to the absence of payment result callbacks or when to check payment status (details).
    • The threshold time is the maximum possible time between the moment a payment is initiated in the payment platform to the moment the web service receives the callback with the payment result. A payment is automatically assigned the decline status if it wasn't processed within the threshold time. For individual customisation of the threshold time limit, contact Eposservice technical support.

Processing scenarios

To perform a purchase by using the WeChat method, the customer needs to scan a QR code via a mobile application.

Figure 1. Purchase by using Payment Page
Figure 2. Purchase by using Gate


Scenarios for performing operations via the main interfaces of the payment platform correspond to those presented in the diagrams. Similarly, when additional features (such as payment links) are used, scenarios for performing operations also correspond to the specifics of those features.

Purchases by using Payment Page

General information

To process a purchase through Payment Page by using the WeChat method, the merchant's web service is required to send a request with all required parameters and signature to the Eposservice URL and receive a callback with the result. The full sequence and special aspects of purchase processing are provided below.

Figure 3. Purchase processing by using Payment Page: step-by-step description
  1. A customer initiates a purchase in the web service.
  2. The web service sends the request for opening Payment Page to the specified Eposservice URL.
  3. The request for opening Payment Page is sent to the payment platform.
  4. The payment platform receives the request and validates the required parameters and signature.
  5. Payment Page is generated based on the project and request parameters.
  6. Payment Page is displayed to the customer.
  7. The customer selects the WeChat method.
  8. The request for processing the payment by using the WeChat method is received by the payment platform.
  9. The payment platform processes the request and sends it to the WeChat service.
  10. The request is processed on the side of the WeChat service.
  11. The data for displaying the payment instructions to the customer is sent from the WeChat service to the payment platform.
  12. The data for displaying the payment instructions is sent from the payment platform to Payment Page.
  13. The payment instructions are displayed to the customer.
  14. The customer completes all required payment steps.
  15. The purchase is processed in the WeChat service.
  16. The result information is displayed to the customer in the WeChat service.
  17. The WeChat service sends a notification about the result to the payment platform.
  18. The payment platform sends the payment result callback to the web service.
  19. The payment platform sends the result information to Payment Page.
  20. The result information is displayed to the customer on Payment Page.

Information about the formats of requests and callbacks used for processing payments by using the WeChat method via Payment Page is presented further in this section; general information about working with the Payment Page API is presented in Interaction concepts.

Request format

There are several things you need to consider when sending purchase requests by using the WeChat method:

  1. The following parameters required for any payment must be specified:
    • project_id—project identifier obtained from Eposservice during integration
    • payment_id—payment identifier unique within the project
    • payment_currency—payment currency code in the ISO-4217 alpha-3 format
    • payment_amount—payment amount in the smallest currency unit
    • customer_id—customer identifier unique within the project
  2. The following parameters required for any payment must be specified: project_id, payment_id, payment_currency, payment_amount, customer_id.
  3. If you need to have the payment form displayed with the WeChat method selected, set the force_payment_method parameter to wechat.
  4. Additionally, any other parameters available for working with Payment Page can be used (details).
  5. After all target parameters are specified, generate a signature (details).

Thus, a correct request for opening the payment form using the WeChat method must contain the project identifier, basic payment information (identifier, amount, and currency code), customer identifier, and signature.

{
   "project_id": 120,
   "payment_id": "580",
   "payment_amount": 10000,
   "payment_currency": "THB",
   "customer_id": "customer1",
   "signature": "kUi2x9dKHAVNU0FYldOcZzUCwX6R\/ekpZhkIQg=="
}
Figure 4. Example of sufficient data in a purchase request
{
   "project_id": 120,
   "payment_id": "580",
   "payment_amount": 10000,
   "payment_currency": "THB",
   "customer_id": "customer1", 
   "signature": "kUi2x9dKHAVNU0FYldOcZzUCwX6R\/ekpZhkIQg=="
}

Callback format

The WeChat method uses the standard format for callbacks to deliver purchase results. For more information, see Handling callbacks.

The following is the example of a callback with information about a 100.00 THB purchase made in the 238 project.

Figure 5. Example of callback data indicating that the purchase has been processed
 {
        "project_id": 238,
        "payment": {
            "id": "TEST_154866061847343331",
            "type": "purchase",
            "status": "success",
            "date": "2025-01-28T08:07:22+0000",
            "method": "wechat",
            "sum": {
                "amount": 10000,
                "currency": "THB"
            },
            "description": "TEST_1548660618473453"
        },
        "operation": {
            "id": 9227000002916,
            "type": "sale",
            "status": "success",
            "date": "2019-01-28T08:07:22+0000",
            "created_date": "2019-01-28T08:06:40+0000",
            "request_id": "67af98801524dfa9c5cddb1a09129",
            "sum_initial": {
                "amount": 10000,
                "currency": "EUR"
            },
            "sum_converted": {
                "amount": 10000,
                "currency": "EUR"
            },
            "provider": {
                "id": 1173,
                "payment_id": "423163569",
                "date": "2019-01-28T08:07:22+0000",
                "auth_code": ""
            },
            "code": "0",
            "message": "Success"
        },
        "signature": "yuuYzrj3kD1cGJrJMo8oJqiyD7GgoTS+mvRA=="
    }

The following is the example of a callback with information about a declined purchase.

Figure 6. Example of callback data indicating that the purchase has been declined
{
        "project_id": 238,
        "payment": {
            "id": "TEST_154996862174000",
            "type": "purchase",
            "status": "decline",
            "date": "2025-02-12T10:56:22+0000",
            "method": "wechat",
            "sum": {
                "amount": 10000,
                "currency": "THB"
            },
            "description": "TEST_154996862174000"
        },
        "customer": {
            "id": "1"
        },
        "operation": {
            "id": 9172000003183,
            "type": "sale",
            "status": "decline",
            "date": "2019-02-12T10:56:22+0000",
            "created_date": "2019-02-12T10:56:18+0000",
            "request_id": "11d4aabf869cb74c0681927ad7",
            "sum_initial": {
                "amount": 10000,
                "currency": "THB"
            },
            "sum_converted": {
                "amount": 10000,
                "currency": "THB"
            },
            "provider": {
                "id": 1169,
                "payment_id": "",
                "auth_code": ""
            },
            "code": "20105",
            "message": "Insufficient funds on customer account"
        },
        "signature": "ghmnbvc1oVdS/mE0AlVHiBOEIObz2tN5SLw=="
    }
}

Useful links

The following articles can be useful when implementing purchases via Payment Page:

Purchases by using Gate

General information

To process a purchase through Gate by using the WeChat method, the merchant's web service is required to do the following:

  1. Send a request with all the required parameters and signature to the Eposservice URL.
  2. Receive an intermediate callback from the payment platform and display the payment instructions to the customer.
  3. Receive the final callback from the payment platform.

The full sequence and special aspects of purchase processing are provided below.



Figure 7. Purchase processing by using Gate: step-by-step description
  1. A customer initiates a purchase by using the WeChat method in the web service.
  2. The web service sends the request for processing the purchase by using Gate to the specified Eposservice URL.
  3. The payment platform receives the request.
  4. The payment platform validates the required parameters and signature in the request.
  5. The payment platform sends the response to the web service with information about the receipt of the request and its validity (details).
  6. The payment platform performs further processing of the request (with parameter consistency check) and sends it to the WeChat service.
  7. The request is processed on the side of the WeChat service.
  8. The data for displaying the payment instructions to the customer is sent from the WeChat service to the payment platform.
  9. The data for displaying the payment instructions is sent from the payment platform to the web service.
  10. The payment instructions are displayed to the customer.
  11. The customer completes all required payment steps.
  12. The purchase is processed in the WeChat service.
  13. The result is displayed to the customer.
  14. The WeChat service sends the payment result notification to the payment platform.
  15. The payment platform sends the payment result callback to the web service.
  16. The customer receives the payment result information from the web service.

Information about the formats of requests and callbacks used for processing payments by using the WeChat method via Gate is presented further in this section. General information about working with the Gate API is presented in Interaction concepts.

Request format

There are several things you need to consider when sending purchase requests by using the WeChat method:

  1. To initiate each purchase, send a separate POST request to the /v2/payment/wallet/wechat/sale endpoint. This endpoint belongs to the group /v2/payment/wallet/{payment_method}/sale.
  2. Each request must include the following objects and parameters:
    • Object general—general purchase information:
      • project_id—project identifier obtained from Eposservice during integration
      • payment_id—payment identifier unique within the project
      • signature—request signature generated after all required parameters are specified (details—in the Signature generation and verification) (details)
    • Object payment—payment information:
      • amount—payment amount in the smallest currency unit
      • currency—payment currency code in the ISO-4217 alpha-3 format
    • Object customer—customer information:
      • id—customer identifier unique within the project
      • ip_address—customer IP address relevant for the initiated payment
  3. Additionally, any other parameters included in the specification can be used.

Thus, a correct purchase request by using the WeChat method must contain the project identifier, basic payment information (identifier, amount, and currency code), customer information, as well as signature.

{
  "general": {
    "project_id": 200,
    "payment_id": "TEST_1559134591371-pz-2",
    "signature": "leNRGu/zTi7tB7T1HPmvelSMQmmWyDUcq3rJKqtw=="
  },
  "customer": {
    "ip_address": "192.0.2.0",
    "id": "customer123"
  },
  "payment": {
    "amount": 1000,
    "currency": "THB"
  }
}
Figure 8. Example of sufficient data in a purchase request
{
  "general": {
    "project_id": 200,
    "payment_id": "TEST_1559134591371-pz-2",
    "signature": "leNRGu/zTi7tB7T1HPmvelSMQmmWyDUcq3rJKqtw=="
  },
  "customer": {
    "ip_address": "192.0.2.0",
    "id": "customer123"
  },
  "payment": {
    "amount": 1000,
    "currency": "THB"
  }
}

Formats of intermediate callbacks for displaying payment instructions

Each payment made with the WeChat method requires displaying payment instructions to customers. To display payment instructions it is necessary to receive an intermediate callback from the payment platform and use the information included in the display_data array. The format of such callbacks is standard (details), and the following objects and parameters are included in the display_data array:

  • type—type of data, the value can be one of the following:
    • qr_img for the object containing the string for displaying the QR code.
    • add_info for the object containing information about the expiration time of the QR code.
  • title—the name of the transferred data that needs to be displayed to the customer, the value can be one of the following:
    • qr_img for the object containing the string for displaying the QR code.
    • expired_timestamp for the object containing information about the expiration time of the QR code.
  • data—the data itself, can contain a string encoded using the Base64 scheme or the UNIX epoch timestamp of when the QR code expires.
Figure 9. display_data example
"display_data": [
    {
      "type": "qr_img",
      "title": "qr_img",
      "data": "data:image/png;base64,iVBORw0KGgo7bMBQAwTjI/a8TkSuQmCC"
    },
    {
      "type": "add_info",
      "title": "expired_timestamp",
      "data": "1756466112"
    }
]

Callback format

The WeChat method uses the standard format for callbacks to deliver purchase results. For more information, see Handling callbacks.

The following is the example of a callback with information about a 1.00 THB purchase made in the 238 project.

Figure 10. Example of callback data indicating that the purchase has been processed
 {
        "project_id": 238,
        "payment": {
            "id": "TEST_154866061847343331",
            "type": "purchase",
            "status": "success",
            "date": "2025-01-28T08:07:22+0000",
            "method": "wechat",
            "sum": {
                "amount": 100,
                "currency": "THB"
            },
            "description": "TEST_1548660618473453"
        },
        "operation": {
            "id": 9227000002916,
            "type": "sale",
            "status": "success",
            "date": "2025-01-28T08:07:22+0000",
            "created_date": "2025-01-28T08:06:40+0000",
            "request_id": "67af98801524dfa9c5cddb1a09129",
            "sum_initial": {
                "amount": 100,
                "currency": "THB"
            },
            "sum_converted": {
                "amount": 100,
                "currency": "THB"
            },
            "provider": {
                "id": 1173,
                "payment_id": "423163569",
                "date": "2025-01-28T08:07:22+0000",
                "auth_code": ""
            },
            "code": "0",
            "message": "Success"
        },
        "signature": "yuuYzrj3kD1cGJrJMo8oJqiyD7GgoTS+mvRA=="
    }

The following is the example of a callback with information about a declined purchase.

Figure 11. Example of callback data indicating that the purchase has been declined
{
        "project_id": 238,
        "payment": {
            "id": "TEST_154996862174000",
            "type": "purchase",
            "status": "decline",
            "date": "2025-02-12T10:56:22+0000",
            "method": "wechat",
            "sum": {
                "amount": 10000,
                "currency": "THB"
            },
            "description": "TEST_154996862174000"
        },
        "customer": {
            "id": "1"
        },
        "operation": {
            "id": 9172000003183,
            "type": "sale",
            "status": "decline",
            "date": "2019-02-12T10:56:22+0000",
            "created_date": "2019-02-12T10:56:18+0000",
            "request_id": "11d4aabf869cb74c0681927ad7",
            "sum_initial": {
                "amount": 10000,
                "currency": "THB"
            },
            "sum_converted": {
                "amount": 10000,
                "currency": "THB"
            },
            "provider": {
                "id": 1169,
                "payment_id": "",
                "auth_code": ""
            },
            "code": "20105",
            "message": "Insufficient funds on customer account"
        },
        "signature": "ghmnbvc1oVdS/mE0AlVJRrqn7HiBOEIObz2tN5SLw=="
    }
}

Useful links

The following articles can be useful when implementing purchases via Gate:

Analysis of payments results

To analyse information about payments made with the WeChat method and other methods, you can use:

  • Dashboard interface toolkit with various lists and analytic panels.
  • Reports in CSV file format, available via the Reports section (one-time and periodically).
  • Data in JSON format, sent by program requests to a specified URL available by using the Data API interface.

If you have any questions, refer to the documentation (Dashboard and Using Data API) and Eposservice technical support.