PromptPay

Introduction

PromptPay uses a redirect-based payment flow. When a customer selects PromptPay at checkout, they are redirected to a hosted page where they can complete the payment using their preferred Thai banking app. Once payment is confirmed, the customer returns to your website or app.

This guide explains the process of integrating PromptPay into your app or website using Payrails.

Pre-requisites

Before you start accepting PromptPay payments with Payrails, there are a few requirements you must meet:

1. Integrate with Payrails using one of our SDKs or our API
2. Configure a new integration account for PromptPay via dLocal as a Payment Service Provider. If you do not have a dLocal integration already configured in your workspace, please follow the dLocal integration setup guide first.
3. Enable PromptPay as a payment method in your dLocal integration configuration. In the Payrails portal, navigate to Settings → Integrations, select your dLocal integration instance, and enable the PromptPay checkbox under Payment methods, then save the account.
4. Enable PromptPay as a payment option in your workflow.
5. Make sure you're sending the PromptPay-specific meta fields in your requests.

Ways to integrate PromptPay

Payrails SDK

The simplest way to use PromptPay with Payrails is to use our drop-in in your checkout flow. With this integration type, no additional work is required to accept payments with PromptPay except for handling success/failure screens for your users.

For a more flexible implementation using our SDK, you can use our genericRedirectButton element. See special instructions here for your client-side implementation.

Server-to-server integration

You can integrate PromptPay by completely managing your own client-side implementation, and using Payrails APIs with a server-to-server integration to process PromptPay payments.

Parse PromptPay from lookup response

With a server-to-server integration, you can call our lookup payment options endpoint to get available payment options. As shown in the example below, you can see promptPay returned as an option of the paymentCompositionOptions.

{
  "name": "lookup",
  "actionId": "0bb6413e-cabb-4074-99e6-9e815c69f25b",
  "executedAt": "2026-03-26T12:00:00.000000000Z",
  "data": {
    "paymentCompositionOptions": [
      {
        "integrationType": "redirect",
        "paymentMethodCode": "promptPay",
        "description": "PromptPay"
      }
    ]
  },
  "links": {
    "execution": "https://api.payrails.io/merchant/workflows/payment-acceptance/executions/83c534ac-13b7-43e6-b04b-f3e8b4eb4424",
    "authorize": {
      "method": "POST",
      "href": "https://api.payrails.io/merchant/workflows/payment-acceptance/executions/83c534ac-13b7-43e6-b04b-f3e8b4eb4424/authorize"
    }
  }
}

Pass PromptPay payment method in request to authorize payment with Payrails

You can then make a request to our authorize a payment endpoint with promptPay as the paymentMethodCode. See an example below:

{
  "executionId": "c0fd1c51-e709-47e5-bfd1-5d1c98f7d990",
  "amount": {
    "value": "50000",
    "currency": "THB"
  },
  "paymentComposition": [
    {
      "integrationType": "redirect",
      "paymentMethodCode": "promptPay",
      "amount": {
        "value": "50000",
        "currency": "THB"
      }
    }
  ],
  "meta": {
    "customer": {
      "name": "Jane Doe",
      "email": "[email protected]",
      "country": {
        "code": "TH"
      }
    }
  },
  "returnInfo": {
    "success": "https://mysuccessurl.com",
    "error": "https://myerrorurl.com"
  }
}

Note on amounts: THB uses 2 decimal places. Amounts should be provided in the smallest currency unit — e.g., 50000 for ฿500.00.

Note: PromptPay is a redirect-based, single-use payment method. After calling the authorize endpoint, the customer will be redirected to a hosted page to complete payment via their banking app. Once confirmed, the customer will be redirected back to the returnInfo.success URL. Make sure to provide valid returnInfo URLs in your authorization request.

Handle the redirect response

After the customer completes the payment, they will be redirected back to your success or error URL. You should then verify the payment status by checking the workflow execution status via the Payrails API or by listening to webhook notifications.

Supported currencies

PromptPay via dLocal supports the following presentment currency:

• THB — Thai Baht

Supported regions / countries

Customer regions

PromptPay is available to customers based in:

• Thailand 🇹🇭

Merchant regions

Merchants enabled for Thailand can accept PromptPay payments via dLocal.

Supported workflows and services