TPV S2S Integration - UPI Intent Flow

You can collect payments using the UPI Intent Flow. In this flow, when customer selects UPI as the payment method, the list of UPI PSP apps is displayed. When the customer selects their preferred app, it opens automatically. They can complete the payment on the UPI PSP app.

Best Practices

Following are a few of the best practices to be followed to accept online payments using UPI Intent Flow:

1. Do not change Intent URL

Do not make changes to the intent URL shared by Razorpay as part of the API response. Making changes to the intent URL can lead to payment failure. 2. Host UPI apps

It is recommended to host the UPI apps on your page/app instead of just hosting the Intent URI where the native Android drawer shows the apps. This improves conversion. 3. Rank UPI Apps by Success Rate

Show the UPI PSP apps in the order of their success rate. 4. Mobile site

If you have higher traffic via mobile site, make sure you provide the option of UPI intent payment to your users using our m-site integration. This will help you achieve better success rates. 5. Gpay SDK

If your UPI transaction volumes are high, you can also explore integrating Gpay SDK. This provides a better user experience and about a 3-5% improvement in success rate.

Prerequisites

• Contact our Support Team to get this feature enabled for your account.
• Keep the API key (combination of Key_Id and Key_Secret) handy for integration.
• Generate API Keys from the Dashboard if you have not done already.
• Configure the payment capture settings on the Dashboard.

UPI Intent Flow

Following is the process for accepting payments using the UPI Intent Flow:

Customers need not enter VPA or phone number as these details are pre-filled and submitted along with the other payment details. While making the payment, customers select the UPI PSP app on your app. The UPI PSP app is launched automatically on their mobile devices, where the payment is completed.

1. The customer selects UPI as the payment method.

   The customer selects UPI as the payment method.

2. The customer chooses their preferred UPI PSP app from the list.

   The customer chooses their preferred UPI PSP app from the list.

3. The UPI PSP app opens automatically and the customer completes the...

   The UPI PSP app opens automatically and the customer completes the payment.

Integration Steps

1. [Create an order](#step-1-create-an-order).

   Create an order.

2. [Initiate Payment using the intent URL](#step-2-initiate-a-payment).

   Initiate Payment using the intent URL.

3. [Store Fields in Your Server](#step-3-store-fields-in-your-server).

   Store Fields in Your Server.

4. [Verify the Signature](#step-4-verify-the-signature).

   Verify the Signature.

Step 1: Create an Order

/orders

Given below is the sample code when method is upi.

Curl

curl -u : \
-X POST https://api.razorpay.com/v1/orders \
-H "Content-Type: application/json" \
-d '{
  "amount": 100,
  "method": "upi",
  "receipt": "BILL13375649",
  "currency": "INR",
  "bank_account": {
    "account_number": "765432123456789",
    "name": "Gaurav Kumar",
    "ifsc": "HDFC0000053"
  }
}'

```java: Java 
RazorpayClient razorpay = new RazorpayClient("[YOUR_KEY_ID]", "[YOUR_KEY_SECRET]");

    JSONObject orderRequest = new JSONObject();
    orderRequest.put("amount", 100); // amount in the smallest currency unit
    orderRequest.put("currency", "INR");
    orderRequest.put("receipt", "BILL13375649");
    orderRequest.put("method", "upi");

    JSONObject bank_account = new JSONObject();
    bank_account.put("account_number", "765432123456789");
    bank_account.put("name", "Gaurav Kumar");
    bank_account.put("ifsc, "HDFC0000053");
    orderRequest.put("bank_account", bank_account);

    Order order = razorpayclient.orders.create(orderRequest);
    System.out.print(order);
        
```python: Python 
import razorpay
client = razorpay.Client(auth=("YOUR_ID", "YOUR_SECRET"))

client.order.create({
{
  "amount": 100,
  "method": "upi",
  "receipt": "BILL13375649",
  "currency": "INR",
  "bank_account": {
    "account_number": "765432123456789",
    "name": "Gaurav Kumar",
    "ifsc": "HDFC0000053"
  }
 })

```php: PHP 
$api = new Api($key_id, $secret);

$api->order->create(array('amount' => 100, 'receipt' => 'BILL13375649', 'method' => 'upi', 'currency' => 'INR', 'bank_account'=> array('account_number'=> '765432123456789','name'=> 'Gaurav Kumar','ifsc'=>'HDFC0000053')));

```csharp: .NET 
RazorpayClient client = new RazorpayClient("[YOUR_KEY_ID]", "[YOUR_KEY_SECRET]");

Dictionary orderRequest = new Dictionary();
orderRequest.Add("amount", 100);
orderRequest.Add("method", "upi");
orderRequest.Add("currency", "INR");
orderRequest.Add("receipt", "receipt#1");
Dictionary bankAccount = new Dictionary();
bankAccount.Add("account_number","765432123456789");
bankAccount.Add("name","Gaurav Kumar");
bankAccount.Add("ifsc","HDFC0000053");
orderRequest.Add("bank_account", bankAccount);

Order order = client.Order.Create(orderRequest);

```ruby: Ruby 
require "razorpay"
Razorpay.setup('YOUR_KEY_ID', 'YOUR_SECRET')

para_attr = {
  "amount": 100,
  "method": "upi",
  "receipt": "BILL13375649",
  "currency": "INR",
  "bank_account": {
    "account_number": "765432123456789",
    "name": "Gaurav Kumar",
    "ifsc": "HDFC0000053"
  }
}  

Razorpay::Order.create(para_attr)

```js: Node.js 
var instance = new Razorpay({ key_id: 'YOUR_KEY_ID', key_secret: 'YOUR_SECRET' })

instance.orders.create({
  "amount": 100,
  "method": "upi",
  "receipt": "BILL13375649",
  "currency": "INR",
  "bank_account": {
    "account_number": "765432123456789",
    "name": "Gaurav Kumar",
    "ifsc": "HDFC0000053"
  }
})

```go: Go 
import ( razorpay "github.com/razorpay/razorpay-go" )
client := razorpay.NewClient("YOUR_KEY_ID", "YOUR_SECRET")

data := map[string]interface{}{
  "amount": 100,
  "method": "upi",
  "receipt": "BILL13375649",
  "currency": "INR",
  "bank_account": map[string]interface{}{
    "account_number": "765432123456789",
    "name": "Gaurav Kumar",
    "ifsc": "HDFC0000053",
  },
}

body, err := client.Order.Create(data, nil)

```json: Response
{
  "id": "order_GAWN9beXgaqRyO",
  "entity": "order",
  "amount": 100,
  "amount_paid": 0,
  "amount_due": 500,
  "currency": "INR",
  "receipt": "BILL13375649",
  "offer_id": null,
  "status": "created",
  "attempts": 0,
  "notes": [],
  "created_at": 1573044247
}

If the user selects the payment method within the Razorpay UI, there is no need to include the method field. Below is a sample code for reference.

Curl

curl -u : \
-X POST https://api.razorpay.com/v1/orders \
-H "Content-Type: application/json" \
-d '{
  "amount": 100,
  "receipt": "BILL13375649",
  "currency": "INR",
  "bank_account": {
    "account_number": "765432123456789",
    "name": "Gaurav Kumar",
    "ifsc": "HDFC0000053"
  }
}'

```java: Java 
RazorpayClient razorpay = new RazorpayClient("[YOUR_KEY_ID]", "[YOUR_KEY_SECRET]");

JSONObject orderRequest = new JSONObject();
orderRequest.put("amount",100);
orderRequest.put("currency","INR");
orderRequest.put("receipt", "receipt#1");
JSONObject notes = new JSONObject();
notes.put("notes_key_1","Tea, Earl Grey, Hot");
notes.put("notes_key_1","Tea, Earl Grey, Hot");
orderRequest.put("notes",notes);

Order order = instance.orders.create(orderRequest);
        
```python: Python 
import razorpay
client = razorpay.Client(auth=("YOUR_ID", "YOUR_SECRET"))

client.order.create({
  "amount": 100,
  "currency": "INR",
  "receipt": "receipt#1",
  "partial_payment":False,
  "notes": {
    "key1": "value3",
    "key2": "value2"
  }
})

```php: PHP 
$api = new Api($key_id, $secret);

$api->order->create(array('receipt' => '123', 'amount' => 100, 'currency' => 'INR', 'notes'=> array('key1'=> 'value3','key2'=> 'value2')));

```csharp: .NET 
RazorpayClient client = new RazorpayClient("[YOUR_KEY_ID]", "[YOUR_KEY_SECRET]");

Dictionary orderRequest = new Dictionary();
orderRequest.Add("amount", 100);
orderRequest.Add("currency", "INR");
orderRequest.Add("receipt", "receipt#1");
Dictionary notes = new Dictionary();
notes.Add("notes_key_1", "Tea, Earl Grey, Hot");
notes.Add("notes_key_2", "Tea, Earl Grey, Hot");
orderRequest.Add("notes", notes);

Order order = client.Order.Create(orderRequest);

```ruby: Ruby 
require "razorpay"
Razorpay.setup('YOUR_KEY_ID', 'YOUR_SECRET')

para_attr = {
  "amount": 100,
  "currency": "INR",
  "receipt": "receipt#1",
  "notes": {
    "key1": "value3",
    "key2": "value2"
  }
}

Razorpay::Order.create(para_attr)

```js: Node.js 
var instance = new Razorpay({ key_id: 'YOUR_KEY_ID', key_secret: 'YOUR_SECRET' })

instance.orders.create({
  "amount": 100,
  "currency": "INR",
  "receipt": "receipt#1",
  "partial_payment": false,
  "notes": {
    "key1": "value3",
    "key2": "value2"
  }
})

```go: Go 
import ( razorpay "github.com/razorpay/razorpay-go" )
client := razorpay.NewClient("YOUR_KEY_ID", "YOUR_SECRET")

data := map[string]interface{}{
  "amount": 100,
  "currency": "INR",
  "receipt": "some_receipt_id",
  "partial_payment": false,
  "notes": map[string]interface{}{
      "key1": "value1",
      "key2": "value2",
    },
}
body, err := client.Order.Create(data, nil)

```json: Response
{
  "id": "order_GAWRjlWkVcRh0V",
  "entity": "order",
  "amount": 100,
  "amount_paid": 0,
  "amount_due": 100,
  "currency": "INR",
  "receipt": "BILL13375649",
  "offer_id": null,
  "status": "created",
  "attempts": 0,
  "notes": [],
  "created_at": 1573044206
}

Request Parameters

amount mandatory : integer The transaction amount expressed in paise (currency supported is INR). For example, for an actual amount of ₹1, the value of this field should be 100.

currency mandatory : string The currency in which the transaction should be made. You can create orders in INR only.

receipt optional : string Receipt number that corresponds to this order, set for your internal reference. Maximum length is 40 characters.

notes optional : json object Key-value pair that can be used to store additional information about the entity. Maximum 15 key-value pairs, 256 characters (maximum) each. For example, "note_key": "Beam me up Scotty”.

method mandatory : string The payment method used to make the payment. If this parameter is not passed, investors will be able to make payments using both netbanking and UPI payment methods. Possible values:

• netbanking: Investors can make payments only using netbanking.
• card: Investors can make payments using debit card.
• upi: Investors can make payments only using UPI.

bank_account mandatory : object Details of the bank account that the investor has provided at the time of registration.

account_number mandatory : string The bank account number from which the investor should make the payment. For example, 765432123456789 Payments will not be processed for an incorrect account number.

name mandatory : string The name linked to the bank account. For example, Gaurav Kumar.

ifsc mandatory : string The bank IFSC. For example, HDFC0000053.

Step 2: Initiate a Payment

/payments/create/upi

Request

  curl -u : \
  -X POST https://api.razorpay.com/v1/payments/create/upi \
  -H "Content-Type: application/json" \
  -d '{
    "amount": 100,
    "currency": "INR",
    "order_id": "order_Ee0biRtLOqzRjP",
    "email": "[e-mail]",
    "contact": "9000090000",
    "method": "upi",
    "ip": "192.168.0.103",
    "referer": "http",
    "user_agent": "Mozilla/5.0",
    "description": "Test flow",
    "notes": {
      "purpose": "UPI test payment"
    },
    "upi": {
      "flow" : "intent"
    }
  }'

```java: Java
RazorpayClient razorpay = new RazorpayClient("[YOUR_KEY_ID]", "[YOUR_KEY_SECRET]");

JSONObject paymentRequest = new JSONObject();
paymentRequest.put("amount", 100);
paymentRequest.put("currency", "INR");
paymentRequest.put("order_id", "order_JZluwjknyWdhnU");
paymentRequest.put("email", "[e-mail]");
paymentRequest.put("contact", "9000090000");
paymentRequest.put("method", "upi");
paymentRequest.put("ip", "192.168.0.103");
paymentRequest.put("referer", "http");
paymentRequest.put("user_agent", "Mozilla/5.0");
paymentRequest.put("description", "Test flow");
JSONObject notes = new JSONObject();
notes.put("purpose", "UPI test payment");
JSONObject upi = new JSONObject();
upi.put("flow", "intent");
paymentRequest.put("notes", notes);
paymentRequest.put("upi", upi);

Payment payment = instance.payments.createUpi(paymentRequest);

```python: Python
import razorpay
client = razorpay.Client(auth=("YOUR_ID", "YOUR_SECRET"))

client.payment.createUpi({
    'amount': 100,
    'currency': 'INR',
    'order_id': 'order_Ee0biRtLOqzRjP',
    'email': '[e-mail]',
    'contact': '9000090000',
    'method': 'upi',
    'ip': '192.168.0.103',
    'referer': 'http',
    'user_agent': 'Mozilla/5.0',
    'description': 'Test flow',
    'notes': {
        'purpose': 'UPI test payment
    '},
    'upi': {
        'flow': 'intent'
    },
})

```php: PHP
$api = new Api($key_id, $secret);

$api->payment->createUpi(array("amount" => 100,"currency" => "INR","order_id" => "order_Jhgp4wIVHQrg5H","email" => "[e-mail]","contact" => "9000090000","method" => "upi","customer_id" => "cust_EIW4T2etiweBmG","ip" => "192.168.0.103","referer" => "http","user_agent" => "Mozilla/5.0","description" => "Test flow","notes" => array("note_key" => "value1"),"upi" => array("flow" => "intent")));

```csharp: .NET
RazorpayClient client = new RazorpayClient(your_key_id, your_secret);

Dictionary paymentRequest = new Dictionary();
paymentRequest.Add("amount",100);
paymentRequest.Add("currency","INR");
paymentRequest.Add("order_id", "order_Z6t7VFTb9xHeOs");
paymentRequest.Add("email", "[e-mail]");
paymentRequest.Add("contact", "9000090000");
paymentRequest.Add("method", "upi");
paymentRequest.Add("ip", "192.168.0.103");
paymentRequest.Add("referer", "http");
paymentRequest.Add("user_agent", "Mozilla/5.0");
paymentRequest.Add("description", "Test flow");
Dictionary notes = new Dictionary();
notes.Add("purpose","UPI test payment");
Dictionary upi = new Dictionary();
upi.Add("flow","intent");
paymentRequest.Add("notes",notes);
paymentRequest.Add("upi",upi);

Payment payment = client.Payment.CreateUpi(paymentRequest);

```ruby: Ruby
require "razorpay"
Razorpay.setup('YOUR_KEY_ID', 'YOUR_SECRET')

para_attr = {
    "amount": 100,
    "currency": "INR",
    "order_id": "order_Ee0biRtLOqzRjP",
    "email": "[e-mail]",
    "contact": "9000090000",
    "method": "upi",
    "ip": "192.168.0.103",
    "referer": "http",
    "user_agent": "Mozilla/5.0",
    "description": "Test flow",
    "notes": {
      "purpose": "UPI test payment"
    },
    "upi": {
      "flow": "intent"
    }
}

Razorpay::Payment.create_upi(para_attr)

```javascript: Node.js
var instance = new Razorpay({ key_id: 'YOUR_KEY_ID', key_secret: 'YOUR_SECRET' })

instance.payments.createUpi({
    "amount": 100,
    "currency": "INR",
    "order_id": "order_Ee0biRtLOqzRjP",
    "email": "[e-mail]",
    "contact": "9000090000",
    "method": "upi",
    "ip": "192.168.0.103",
    "referer": "http",
    "user_agent": "Mozilla/5.0",
    "description": "Test flow",
    "notes": {
        "purpose": "UPI test payment"
    },
    "upi": {
        "flow": "intent"
    }
});

```go: Go
import ( razorpay "github.com/razorpay/razorpay-go" )
client := razorpay.NewClient("YOUR_KEY_ID", "YOUR_SECRET")

para_attr: = map[string] interface {} {
    "amount": 100,
    "currency": "INR",
    "order_id": "order_Ee0biRtLOqzRjP",
    "email": "[e-mail]",
    "contact": "9000090000",
    "method": "upi",
    "ip": "192.168.0.103",
    "referer": "http",
    "user_agent": "Mozilla/5.0",
    "description": "Test flow",
    "notes": map[string] interface {} {
            "purpose": "UPI test payment",
        },
        "upi": map[string] interface {} {
            "flow": "intent",
        },
}
body, err: = client.Payment.CreateUpi(para_attr, nil)

``` json: Response
{
  "razorpay_payment_id": "pay_CMeM6XvOPGFiF",
  "link": "upi://pay?pa=success@razorpay&pn=xyz&tr=xxxxxxxxxxx&tn=gourav&am=1&cu=INR&mc=xyzw"
}

Do Not Make Changes to Link Received in Response

Do not make changes to the link you receive in the response. This is the Razorpay Intent URL. Making changes to this URL can lead to payment failure or other unexpected errors with the payment.

Request Parameters

Following are the request parameters for the API:

amount mandatory : integer The amount associated with the payment in the smallest unit of the supported currency. For example, 2000 means ₹20.

currency mandatory : string ISO code of the currency associated with the payment amount. In this case, it is INR.

order_id mandatory : string Unique identifier of the order obtained from the response of the previous step.

method mandatory : string The payment method used to make the payment. Possible values:

• netbanking
• upi

notes optional : json object Key-value pair used to store additional information about the entity. Maximum 15 key-value pairs, 256 characters (maximum) each. For example, "note_key": "Beam me up Scotty”.

description optional : string Descriptive text of the payment.

contact mandatory : string Phone number of the customer.

email mandatory : string Email address of the customer.

callback_url optional : string URL where Razorpay will submit the final payment status.

ip mandatory : string The client’s browser IP address. For example, 117.217.74.98

referer mandatory : string Value of the referer header passed by the client’s browser. For example, https://example.com/.

user_agent mandatory : string Value of the user_agent header passed by client’s browser. For example, Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36

upi mandatory : Details of the UPI payment

flow : string Type of the UPI method. In this case, it is intent.

You will get the UPI Intent URI as part of the payment response.

To pass the payment data to the respective UPI app and to initiate the payment, use the following code:

Pass data to UPI app

Intent i = new Intent(Intent.ACTION_VIEW);
        i.setData(Uri.parse(url)); //uri from the create S2S payment response
        i.setPackage(packageName); //package name from the `upi://pay` intent response

activity.startActivityForResult(i,2561); //unique activity code to get the callback

Step 3: Store Fields in Your Server

A successful payment returns the following fields to the Checkout form.

Success Callback

• You need to store these fields in your server.
• You can confirm the authenticity of these details by verifying the signature in the next step.

Success Callback

{
  "razorpay_payment_id": "pay_29QQoUBi66xm2f",
  "razorpay_order_id": "order_9A33XWu170gUtm",
  "razorpay_signature": "9ef4dffbfd84f1318f6739a3ce19f9d85851857ae648f114332d8401e0949a3d"
}

razorpay_payment_id : string Unique identifier for the payment returned by Checkout only for successful payments.

razorpay_order_id : string Unique identifier for the order returned by Checkout.

razorpay_signature : string Signature returned by the Checkout. This is used to verify the payment.

Step 4: Verify the Payment Signature

This is a mandatory step to confirm the authenticity of the details returned to the Checkout form for successful payments.

To verify the razorpay_signature returned to you by the Checkout form:

1. Create a signature in your server using the following attributes:

   • order_id: Retrieve the order_id from your server. Do not use the razorpay_order_id returned by Checkout.
   • razorpay_payment_id: Returned by Checkout.
   • key_secret: Available in your server. The key_secret that was generated from the Dashboard.

2. Use the SHA256 algorithm, the razorpay_payment_id and the order_id to construct a HMAC hex digest as shown below:

   HMAC Hex Digest

   generated_signature = hmac_sha256(order_id + "|" + razorpay_payment_id, secret);
   
     if (generated_signature == razorpay_signature) {
       payment is successful
     }
   

3. If the signature you generate on your server matches the razorpay_signature returned to you by the Checkout form, the payment received is from an authentic source.

Generate Signature on Your Server

Given below is the sample code for payment signature verification:

Java

RazorpayClient razorpay = new RazorpayClient("[YOUR_KEY_ID]", "[YOUR_KEY_SECRET]");

String secret = "EnLs21M47BllR3X8PSFtjtbd";

JSONObject options = new JSONObject();
options.put("razorpay_order_id", "order_IEIaMR65cu6nz3");
options.put("razorpay_payment_id", "pay_IH4NVgf4Dreq1l");
options.put("razorpay_signature", "0d4e745a1838664ad6c9c9902212a32d627d68e917290b0ad5f08ff4561bc50f");

boolean status =  Utils.verifyPaymentSignature(options, secret);

```php: PHP
$api = new Api($key_id, $secret);

$api->utility->verifyPaymentSignature(array('razorpay_order_id' => $razorpayOrderId, 'razorpay_payment_id' => $razorpayPaymentId, 'razorpay_signature' => $razorpaySignature));

```ruby: Ruby
require "razorpay"
Razorpay.setup('YOUR_KEY_ID', 'YOUR_SECRET')

payment_response = {
       razorpay_order_id: 'order_IEIaMR65cu6nz3',
       razorpay_payment_id: 'pay_IH4NVgf4Dreq1l',
       razorpay_signature: '0d4e745a1838664ad6c9c9902212a32d627d68e917290b0ad5f08ff4561bc50f'
     }
Razorpay::Utility.verify_payment_signature(payment_response)

```python: Python
import razorpay
client = razorpay.Client(auth=("YOUR_ID", "YOUR_SECRET"))

client.utility.verify_payment_signature({
  'razorpay_order_id': razorpay_order_id,
  'razorpay_payment_id': razorpay_payment_id,
  'razorpay_signature': razorpay_signature
  })

```c: .NET
RazorpayClient client = new RazorpayClient("[YOUR_KEY_ID]", "[YOUR_KEY_SECRET]");

Dictionary options = new Dictionary();
options.Add("razorpay_order_id", "order_IEIaMR65");
options.Add("razorpay_payment_id", "pay_IH4NVgf4Dreq1l");
options.Add("razorpay_signature", "0d4e745a1838664ad6c9c9902212a32d627d68e917290b0ad5f08ff4561bc50");

Utils.verifyPaymentSignature(options);

```nodejs: Node.js
var instance = new Razorpay({ key_id: 'YOUR_KEY_ID', key_secret: 'YOUR_SECRET' })

var { validatePaymentVerification, validateWebhookSignature } = require('./dist/utils/razorpay-utils');
validatePaymentVerification({"order_id": razorpayOrderId, "payment_id": razorpayPaymentId }, signature, secret);

```Go: Go
import ( razorpay "github.com/razorpay/razorpay-go" )
client := razorpay.NewClient("YOUR_KEY_ID", "YOUR_SECRET")

params := map[string]interface{}{
 "razorpay_order_id": "order_IEIaMR65cu6nz3",
 "razorpay_payment_id": "pay_IH4NVgf4Dreq1l",
}

signature := "0d4e745a1838664ad6c9c9902212a32d627d68e917290b0ad5f08ff4561bc50f";
secret := "EnLs21M47BllR3X8PSFtjtbd";
utils.VerifyPaymentSignature(params, signature, secret)

Post Signature Verification

After you have completed the integration, you can set up webhooks, make test payments, replace the test key with the live key and integrate with other APIs.

Payment Capture Settings

After payment is authorized, you need to capture it to settle the amount to your bank account as per the settlement schedule. Payments that are not captured are auto-refunded after a fixed time.

Watch Out

• You should deliver the products or services to your customers only after the payment is captured. Razorpay automatically refunds all the uncaptured payments.

• You can track the payment status using our Fetch a Payment API or webhooks.

  Authorized payments can be automatically captured. You can auto-capture all payments using global settings on the Razorpay Dashboard. Know more about capture settings for payments.

Watch Out!

Payment capture settings work only if you have integrated with Orders API on your server side. Know more about the Orders API.

Each authorized payment can also be captured individually. You can manually capture payments using Payment Capture API or Dashboard. Know more about capture settings for payments.

Related Information

• Webhooks (Recommended)
• Error Codes (Recommended)
• How Payment Gateway Works
• Payment States
• Settlements
• Refunds