User-Presented Mode (B scan C) NEW

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Accept in-store payments from WeChat Pay users through your point-of-sale system (POS) using the WeChat Pay User-Presented Mode (B scan C) payment method.

This guide walks you through the payment flow and details on how to implement.

How to enable

  • Supported Countries: Thailand
  • Minimum API version: 2017-11-02

To enable User-Presented Mode (B scan C), send an email requesting this feature to You will need to review and accept new terms and conditions.

Payment flow

Customers paying via User-Presented Mode (B scan C) present their payment code (barcode or QR code) to you. You must scan the payment code using a barcode reader and use it to create a new charge.

payment flow

❶ The customer opens an WeChat Pay application on their mobile phone. Then, the customer chooses to generate a QR code in the application and displays to the merchant. ❷ The merchant scans the QR code with QR code reader. ❸ The customer confirms payment in the application. ❹ The payment successful page is displayed after the payment is made.


To create a charge using User-Presented Mode (B scan C), make the following API requests.

  1. Create a new charge specifying the required parameters.
  2. After receiving the charge completion webhook event, retrieve the charge to verify its status (optional, but recommended).

Use your secret key to create the User-Presented Mode (B scan C) charge.

Creating a charge

When the payer confirms they wish to use this payment method, create a new charge specifying the following parameters: amount, currency, source[type] (wechat_pay_upm), and source[barcode].

Parameter Type Description
amount integer (required) Amount in subunits of source currency
currency string (required) THB
source[type] string (required) Payment source type wechat_pay_upm
source[barcode] string (required) Payment code (QR code or barcode) number read by your scanner

The following example demonstrates how to create a new charge using curl. Replace $OMISE_SECRET_KEY with the test secret key found on your dashboard.

curl \
  -d "amount=150000" \
  -d "currency=THB" \
  -d "source[type]=wechat_pay_upm" \
  -d "source[barcode]=130991292552725093"
  "object": "charge",
  "id": "chrg_test_5y4zomdqoboas2g9rds",
  "location": "/charges/chrg_test_5y4zomdqoboas2g9rds",
  "amount": 150000,
  "acquirer_reference_number": null,
  "net": 147352,
  "fee": 2475,
  "fee_vat": 173,
  "interest": 0,
  "interest_vat": 0,
  "funding_amount": 150000,
  "refunded_amount": 0,
  "transaction_fees": {
    "fee_flat": "0.0",
    "fee_rate": "1.65",
    "vat_rate": "7.0"
  "platform_fee": {
    "fixed": null,
    "amount": null,
    "percentage": null
  "currency": "THB",
  "funding_currency": "THB",
  "ip": null,
  "refunds": {
    "object": "list",
    "data": [],
    "limit": 20,
    "offset": 0,
    "total": 0,
    "location": "/charges/chrg_test_5y4zomdqoboas2g9rds/refunds",
    "order": "chronological",
    "from": "1970-01-01T00:00:00Z",
    "to": "2023-12-18T10:18:51Z"
  "link": null,
  "description": null,
  "metadata": {},
  "card": null,
  "source": {
    "object": "source",
    "id": "src_test_5y4zomdhmxjjsjbu7jv",
    "livemode": false,
    "location": "/sources/src_test_5y4zomdhmxjjsjbu7jv",
    "amount": 150000,
    "barcode": "130991292552725093",
    "bank": null,
    "created_at": "2023-12-18T10:18:51Z",
    "currency": "THB",
    "email": null,
    "flow": "offline",
    "installment_term": null,
    "ip": null,
    "absorption_type": null,
    "name": null,
    "mobile_number": null,
    "phone_number": null,
    "platform_type": null,
    "scannable_code": {
      "object": "barcode",
      "type": "qr",
      "image": {
        "object": "document",
        "livemode": false,
        "id": "docu_test_5y4zomfmlti0uqm24u6",
        "deleted": false,
        "filename": "632640704557555841.svg",
        "location": "/charges/chrg_test_5y4zomdqoboas2g9rds/documents/docu_test_5y4zomfmlti0uqm24u6",
        "kind": "qr",
        "download_uri": "",
        "created_at": "2023-12-18T10:18:51Z"
    "billing": null,
    "shipping": null,
    "items": [],
    "references": null,
    "provider_references": null,
    "store_id": null,
    "store_name": null,
    "terminal_id": null,
    "type": "wechat_pay_upm",
    "zero_interest_installments": null,
    "charge_status": "pending",
    "receipt_amount": null,
    "discounts": []
  "schedule": null,
  "customer": null,
  "dispute": null,
  "transaction": null,
  "failure_code": null,
  "failure_message": null,
  "status": "pending",
  "authorize_uri": null,
  "return_uri": null,
  "created_at": "2023-12-18T10:18:51Z",
  "paid_at": null,
  "expires_at": "2023-12-19T10:18:51Z",
  "expired_at": null,
  "reversed_at": null,
  "zero_interest_installments": false,
  "branch": null,
  "terminal": null,
  "device": null,
  "authorized": false,
  "capturable": false,
  "capture": true,
  "disputable": false,
  "livemode": false,
  "refundable": false,
  "partially_refundable": false,
  "reversed": false,
  "reversible": false,
  "voided": false,
  "paid": false,
  "expired": false

Setting the charge to expire

User-Presented Mode (B scan C) charges that have not yet been authorized (status=pending) can be set to expire immediately. In effect, this cancels the charge.

curl$CHARGE_ID/expire \
  -X POST \

Completing the charge

At this point, you have created a new charge with its status set to pending. Other possible values for charge status are successful, failed, and expired.

The following sections detail how to authorize a charge, receive its completion webhook event, and update its status.

sequenceDiagram participant customer participant merchant participant participant payment provider customer->>merchant: Present payment code for scanning merchant->> Create charge using payment code>>merchant: Return charge Send "charge.create" webhook customer->>payment provider: Provide charge authorization payment provider-->>customer: Return payment result payment provider-->> Return payment result Send "charge.complete" webhook

Receiving the charge completion event

The best way to be notified about the completion of a charge is using webhook events.

Set up a location on the merchant server to receive webhook events, and add this location as a webhook endpoint on the dashboard.

Checking the charge status

After receiving this event, retrieve the charge using its id and confirm that its status matches the status of the charge contained in the event.

If the value of status is successful, you got paid.

If the value of status is failed, check the failure_code and failure_message in the charge object for an explanation.

Possible failure codes are as follows.

Failure Code Description
payment_expired Payment expired.
payment_rejected Payment rejected by issuer.
invalid_account Valid account for payment method not found.
insufficient_fund Insufficient funds in the account or the payment method has reached its limit.
failed_processing General payment processing failure.


User-Presented Mode (B scan C) charges can be partially or fully refunded within 90 days of the transaction date.


  • Minimum: 2000 (THB 20.00)
  • Maximum: 15000000 (THB 150,000.00)

How to check the public key and secret key

For information on how to obtain and check the public and secret keys, please refer to this document.

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