PromptPay

Enable your customers to make purchases directly from their bank accounts using PromptPay. PromptPay helps your business receive secure and instant payments from buyers across Thailand. No need to fill out payment details; customers can simply scan your QR code for faster checkout.

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 PromptPay, send an email requesting this feature to support@opn.ooo. You will need to review and accept new terms and conditions.

Payment flow

Customers paying via PromptPay go through an offline payment flow. This means that once the charge is created, it can only be authorized offline. In this case, the customer must scan the generated QR code using a banking app on their phone to complete the flow.

After the customer selects PromptPay as their preferred payment method, your site should generate the PromptPay QR code. The following screenshots demonstrate two flows: one using a desktop browser and one using a mobile browser. In both cases, once the QR code is visible, the customer must scan it to complete the payment.

Using a Desktop Browser

To scan the QR code, the customer logs into their bank app on their mobile phone ❷. The customer scans the code using their bank app ❸. The customer confirms the purchase using the bank app ❹. Once you receive a webhook completion event, confirm the payment with the user ❺.

Using a Mobile Browser

To scan the QR code, the customer takes a screenshot of the QR code ❶ and logs into their bank using their mobile phone ❷. The customer loads the screenshot containing the QR code using their bank app ❸. The customer confirms the purchase using the bank app ❹. Once you receive a webhook completion event, confirm the payment with the user ❺.

Implementation

To create a charge using PromptPay, make the following API requests.

1. Create a new payment source (type: promptpay) using Omise.js or one of the mobile SDKs (iOS and Android)
2. Create a new charge using the identifier of the source created in Step 1.
3. After receiving the charge completion webhook event, retrieve the charge to verify its status (optional, but recommended).

Use your public key to create the PromptPay source on the client (a customer's browser or mobile phone). Use your secret key to create the PromptPay charge on the server.

If both the creation and charge of a source must happen server-side, you can create and charge the source in a single API request using your secret key.

Creating a source

When the customer confirms that they wish to pay with this payment method, create a new source specifying the amount, currency, and type.

The following examples demonstrate the creation of a new PromptPay source for ฿4,000. Replace the omise_public_key and $OMISE_PUBLIC_KEY variables with the test public key found on your dashboard.

Using Omise.js, the type parameter is supplied as the first argument to the createSource method.

Omise.setPublicKey(omise_public_key);

Omise.createSource('promptpay', {
  "amount": 400000,
  "currency": "THB"
}, function(statusCode, response) {
  console.log(response)
});

For testing, you can create the same request using curl.

curl https://api.omise.co/sources \
  -u $OMISE_PUBLIC_KEY: \
  -d "amount=400000" \
  -d "currency=THB" \
  -d "type=promptpay"

{
  "object": "source",
  "id": "src_5vcd3haifubvfckkrms",
  "livemode": true,
  "location": "/sources/src_5vcd3haifubvfckkrms",
  "amount": 400000,
  "barcode": null,
  "bank": null,
  "created_at": "2023-04-05T03:46:53Z",
  "currency": "THB",
  "email": null,
  "flow": "offline",
  "installment_term": null,
  "absorption_type": null,
  "name": null,
  "mobile_number": null,
  "phone_number": null,
  "platform_type": null,
  "scannable_code": null,
  "billing": null,
  "shipping": null,
  "items": [],
  "references": null,
  "store_id": null,
  "store_name": null,
  "terminal_id": null,
  "type": "promptpay",
  "zero_interest_installments": null,
  "charge_status": "unknown",
  "receipt_amount": null,
  "discounts": []
}

The id attribute is the source identifier (begins with src).

Creating a charge

Create a charge specifying the parameters source, amount, and currency.

• source specifies the source identifier.
• amount and currency must match amount and currency of the source.

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

curl https://api.omise.co/charges \
  -u $OMISE_SECRET_KEY: \
  -d "amount=400000" \
  -d "currency=THB" \
  -d "source=$SOURCE_ID"

{
  "object": "charge",
  "id": "chrg_5vcd3hg9eh4dm925lbl",
  "location": "/charges/chrg_5vcd3hg9eh4dm925lbl",
  "amount": 400000,
  "net": 392938,
  "fee": 6600,
  "fee_vat": 462,
  "interest": 0,
  "interest_vat": 0,
  "funding_amount": 400000,
  "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_5vcd3hg9eh4dm925lbl/refunds",
    "order": "chronological",
    "from": "1970-01-01T00:00:00Z",
    "to": "2023-04-05T03:46:54Z"
  },
  "link": null,
  "description": null,
  "metadata": {},
  "card": null,
  "source": {
    "object": "source",
    "id": "src_5vcd3gzn1btjht2zeto",
    "livemode": true,
    "location": "/sources/src_5vcd3gzn1btjht2zeto",
    "amount": 400000,
    "barcode": null,
    "bank": null,
    "created_at": "2023-04-05T03:46:51Z",
    "currency": "THB",
    "email": null,
    "flow": "offline",
    "installment_term": 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": true,
        "id": "docu_5vcd3hjr0yg6cdhxkdl",
        "deleted": false,
        "filename": "qrcode.svg",
        "location": "/charges/chrg_5vcd3hg9eh4dm925lbl/documents/docu_5vcd3hjr0yg6cdhxkdl",
        "kind": "qr",
        "download_uri": "https://api.omise.co/charges/chrg_5vcd3hg9eh4dm925lbl/documents/docu_5vcd3hjr0yg6cdhxkdl/downloads/6BE6D6CB037C020E",
        "created_at": "2023-04-05T03:46:54Z"
      }
    },
    "billing": null,
    "shipping": null,
    "items": [],
    "references": null,
    "store_id": null,
    "store_name": null,
    "terminal_id": null,
    "type": "promptpay",
    "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": "2023-04-05T03:46:53Z",
  "paid_at": null,
  "expires_at": "2023-04-06T03:46:54Z",
  "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": true,
  "refundable": false,
  "reversed": false,
  "reversible": false,
  "voided": false,
  "paid": false,
  "expired": false
}

Setting the QR code to expire

By default, the QR code expires 24 hours after creation.

The default expiry time can also be changed to a certain period after creation (e.g. 5 mins after creation). Please contact support@opn.ooo to update the setting.

You can also assign different expiration periods to each QR code by entering a timestamp not exceeding 24 hours in the expires_at field of the Charge API (The countdown will start after the QR code generation). If the timestamp is entered correctly, the QR code will expire at the designated time instead of the default period.

curl https://api.omise.co/charges \
  -u $OMISE_SECRET_KEY: \
  -d "amount=400000" \
  -d "currency=THB" \
  -d "source[type]=promptpay"
  -d "expires_at=2020-07-01T15:00:00Z"

Creating a source and charge

Alternatively, you can create and charge a source in a single API request.

curl https://api.omise.co/charges \
  -u $OMISE_SECRET_KEY: \
  -d "amount=400000" \
  -d "currency=THB" \
  -d "source[type]=promptpay"

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.

This sequence diagram shows the entire flow.

Authorizing the charge

Present the customer with QR code generated at charge creation. To authorize the charge, the customer scans the QR code using their phone.

You can simulate the authorization phase in test mode. Go to the specific charge on the dashboard, click on Actions and manually mark the charge as Successful or Failed.

Find the QR code nested within the charge object as follows:

charge:
  source:
    scannable_code:
      image:
        download_uri: QR code image to present to the customer

{
  "object": "barcode",
  "type": "qr",
  "image": {
    "object": "document",
    "livemode": true,
    "id": "docu_5vcd3h3p8dr84hcndng",
    "deleted": false,
    "filename": "qrcode.svg",
    "location": "/charges/chrg_5vcd3h1xpvyzm2mk12d/documents/docu_5vcd3h3p8dr84hcndng",
    "kind": "qr",
    "download_uri": "https://api.omise.co/charges/chrg_5vcd3h1xpvyzm2mk12d/documents/docu_5vcd3h3p8dr84hcndng/downloads/CF36BE7CA0302B05",
    "created_at": "2023-04-05T03:46:52Z"
  }
}

Receiving the charge completion event

The best way for you to be notified of the completion of a charge is using webhook events. Set up a location on your server to receive webhook events, and add this location as a webhook endpoint on the dashboard.

Once a charge is completed, a POST request will be sent to this endpoint with the charge response embedded.

The key attribute for the event object contains charge.complete and the data attribute contains the charge object. See Events API for event object structure.

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 listed below.

Voids and refunds

PromptPay charges cannot be voided or refunded through Opn Payments.

Limits

• Minimum: 2000 (THB20.00)
• Maximum: 15000000 (THB150,000.00)

Next steps

• Charge API
• Source API
• Webhooks API