### Project Setup for Development

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Configures the package.json file for running both the client and server applications concurrently. It defines scripts for starting the client, server, and a combined start command. This setup is crucial for local development and testing.

```json
"proxy": "http://localhost:3030",
"scripts": {
    "start-client": "react-scripts start",
    "start-server": "nodemon server.js",
    "start": "concurrently \"npm run start-client\" \"npm run start-server\""
}
```

--------------------------------

### Install Golang PayOS SDK

Source: https://payos.vn/docs/sdks/back-end/golang

Install the payos-lib-golang library using the go get command. This command fetches and installs the specified version of the SDK, making it available for use in your Go projects.

```bash
go get github.com/payOSHQ/payos-lib-golang/v2
```

--------------------------------

### Start Development Server

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Command to start both the client and server applications simultaneously using npm. This command utilizes the 'start' script defined in package.json, enabling a full-stack development environment.

```bash
npm run start
```

--------------------------------

### Start Application Server

Source: https://payos.vn/docs/checkout/quick-start-payos-hosted-page

Starts the application server using npm. This command assumes you have a 'start' script defined in your package.json, typically pointing to your main server file.

```bash
npm start
```

--------------------------------

### Run Development Servers

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Commands to start both the PHP development server for the backend and the React development server for the frontend. This setup allows for local testing of the PayOS integration.

```bash
# server side
php -S localhost:3030 --docroot=public

# client side
npm start
```

--------------------------------

### Java SDK Setup

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Instructions for adding the PayOS Java SDK to your Maven or Gradle project.

```APIDOC
## Java SDK Setup

### Maven
Add the following code to your POM and replace VERSION with your desired version.

```xml
<dependency>
  <groupId>vn.payos</groupId>
  <artifactId>payos-java</artifactId>
  <version>{VERSION}</version>
</dependency>
```

### Gradle
Add the following code to your build.gradle and replace VERSION with your desired version.

```groovy
implementation 'vn.payos:payos-java:{VERSION}'
```
```

--------------------------------

### Javascript: Example Usage of Signature Verification

Source: https://payos.vn/docs/tich-hop-webhook/kiem-tra-du-lieu-voi-signature

An example demonstrating the usage of `verifySignatureBrowser` with predefined payout data, a checksum key, and an expected signature. This snippet illustrates how to check the integrity of payout transaction data.

```javascript
const payoutChecksumKey = '6e91f59952acc8918c49c4a8e380136d66d1fbbf3375926840a8a7e434d4b325';
const expectedSignature = '34d500c4e17feaad8fab528ac3ae089353e276ca9fb4c6654c06ffdfbd88cc5d';
const payoutData = {
  code: '00',
  desc: 'success',
  data: {
    payouts: [
      {
        id: 'batch_8f9520b9341144f38b9f5fbfa317db8e',
        referenceId: 'payout_1753061728877',
        transactions: [
          {
            id: 'batch_txn_fdb348c0570a4cb99009da22f9504898',
            referenceId: 'payout_1753061728877_0',
            amount: 2000,
            description: 'batch payout',
            toBin: '970422',
            toAccountNumber: '0123456789',
            toAccountName: 'NGUYEN VAN A',
            reference: '103269845',
            transactionDatetime: '2025-07-21T08:35:40+07:00',
            errorMessage: null,
            errorCode: null,
            state: 'SUCCEEDED',
          },
          {
            id: 'batch_txn_d94d371c079f4fc0ab7154e1576629d8',
            referenceId: 'payout_1753061728877_1',
            amount: 2000,
            description: 'batch payout',
            toBin: '970422',
            toAccountNumber: '0123456789',
            toAccountName: 'NGUYEN VAN A',
            reference: '103269846',
            transactionDatetime: '2025-07-21T08:35:44+07:00',
            error
```

--------------------------------

### Run Flask Development Server

Source: https://payos.vn/docs/checkout/quick-start-payos-hosted-page

Start the Flask development server to run your application locally. This command assumes you have Flask installed and your application file is named `server.py`. The server will be accessible at `http://localhost:3030`.

```bash
flask run --port=3030
```

--------------------------------

### Installation

Source: https://payos.vn/docs/sdks/back-end/node

Install the `@payos/node` package using npm or yarn.

```APIDOC
## Installation

Install the `@payos/node` package using npm or yarn:

```bash
npm install @payos/node
# or
yarn add @payos/node
```
```

--------------------------------

### Install PayOS Library for Python

Source: https://payos.vn/docs/checkout/quick-start-payos-hosted-page

This command installs the PayOS library for Python using pip. Ensure you have Python and pip installed on your system before running this command.

```bash
pip install payos

```

--------------------------------

### Run Go Server

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Executes the Go server application. This command is used to start your local server for testing the PayOS integration.

```bash
go run server.go
```

--------------------------------

### Install PayOS .NET SDK

Source: https://payos.vn/docs/sdks/back-end/net

Installs the 'payOS' package using the .NET CLI. This is the first step to integrate PayOS functionality into your .NET Core application.

```bash
dotnet add package payOS
```

--------------------------------

### Run Server and Client

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Instructions for running the server and client-side applications. The server is run using Flask on port 3030, and the client is started with npm. Access the payment link creation interface at http://localhost:3000.

```shell
# server side
flask run --port=3030

# client side
npm start
```

--------------------------------

### Install PayOS Python SDK

Source: https://payos.vn/docs/sdks/back-end/python

Install the PayOS Python library using pip. This command ensures you have the latest version of the SDK available for your project.

```bash
# Windows
pip install payos

# Linux/macOS
pip3 install payos
```

--------------------------------

### Install Node.js SDK with npm and yarn

Source: https://payos.vn/docs/sdks/intro

Instructions for installing the PayOS Node.js SDK using both npm and yarn package managers. This SDK facilitates server-side integration with PayOS.

```bash
npm install @payos/node --save
```

```bash
yarn add @payos/node
```

--------------------------------

### Install @payos/node SDK

Source: https://payos.vn/docs/sdks/back-end/node

Install the `@payos/node` package using npm or yarn. This is the first step to integrate PayOS functionalities into your NodeJS application.

```bash
npm install @payos/node
# hoặc
yarn add @payos/node
```

--------------------------------

### Install payos-checkout Library

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

How to install the payos-checkout JavaScript library using a CDN link.

```APIDOC
## Install payos-checkout Library

### Install payos-checkout using CDN link

```html
<script src="https://cdn.payos.vn/payos-checkout/v1/stable/payos-initialize.js"></script>
```
```

--------------------------------

### Run Sample payOS Server

Source: https://payos.vn/docs/checkout/quick-start-payos-hosted-page

Execute the sample payOS server application using the provided Java command. This command requires the payos-payment JAR file with dependencies and specifies the main class to run. Access the server at http://localhost:3030 to test payment link creation.

```bash
java -cp .\target\payos-payment-1.0-SNAPSHOT-jar-with-dependencies.jar vn.payos.sample.Server
```

--------------------------------

### Install PayOS Checkout Library (yarn)

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Install the payos-checkout library using yarn for frontend integration.

```bash
yarn add @payos/payos-checkout
```

--------------------------------

### Install PayOS Checkout Library (npm)

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Install the payos-checkout library using npm for frontend integration.

```bash
npm install @payos/payos-checkout
```

--------------------------------

### Create Payment Link with Go

Source: https://payos.vn/docs/checkout/quick-start-payos-hosted-page

This Go code snippet demonstrates how to create a payment link using the PayOS library. It initializes the PayOS client with credentials and defines a handler to create a payment link request with order details. Dependencies include the payOS-lib-golang library. It takes order information as input and returns a payment link response.

```go
package main

import (
	"log"
	"net/http"
	"time"

	"github.com/payOSHQ/payos-lib-golang/v2"
)

var payOSClient *payos.PayOS

func main() {
	// Keep your PayOS key protected by including it by an env variable
	const clientId = "YOUR_CLIENT_ID"
	const apiKey = "YOUR_API_KEY"
	const checksumKey = "YOUR_CHECKSUM_KEY"

	var err error
	payOSClient, err = payos.NewPayOS(&payos.PayOSOptions{
		ClientID:    clientId,
		APIKey:      apiKey,
		ChecksumKey: checksumKey,
	})
	if err != nil {
		log.Fatalf("Failed to create PayOS client: %v", err)
	}

	http.Handle("/", http.FileServer(http.Dir("public")))
	http.HandleFunc("/create-payment-link", createPaymentLink)
	addr := "localhost:3030"
	log.Printf("Listening on %s", addr)
	log.Fatal(http.ListenAndServe(addr, nil))
}

func createPaymentLink(w http.ResponseWriter, r *http.Request) {
	domain := "http://localhost:3030"
	paymentLinkRequest := payos.CreatePaymentLinkRequest{
		OrderCode:   time.Now().UnixNano() / int64(time.Millisecond),
		Amount:      2000,
		Description: "Thanh toan don hang",
		CancelUrl:   domain,
		ReturnUrl:   domain,
	}

	paymentLinkResponse, err := payOSClient.PaymentRequests.Create(r.Context(), &paymentLinkRequest)
```

--------------------------------

### Install PayOS Checkout Library

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Installs the payos-checkout library using either npm or yarn package managers. This library is essential for integrating PayOS payment functionalities into your front-end application.

```bash
npm install @payos/payos-checkout
# hoặc
yarn add @payos/payos-checkout
```

--------------------------------

### Install PayOS NuGet Package for .NET

Source: https://payos.vn/docs/checkout/quick-start-payos-hosted-page

These commands show how to add the PayOS library to your .NET project using NuGet Package Manager. This is a prerequisite for using PayOS functionalities in a .NET environment. It involves using either the .NET CLI or the Package Manager Console.

```bash
dotnet add package payOS
```

```powershell
Install-Package payOS
```

--------------------------------

### Install PayOS Checkout Libraries (npm/yarn)

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Installs the PayOS checkout library for front-end integration using either npm or yarn. This library provides hooks and components for embedding the PayOS payment interface into your React application.

```bash
npm install @payos/payos-checkout
```

```bash
yarn add @payos/payos-checkout
```

--------------------------------

### Initialize PayOS Client in Go

Source: https://payos.vn/docs/sdks/back-end/golang

Initialize the PayOS client by providing your Client ID, API Key, and Checksum Key. These credentials are typically loaded from environment variables. The function returns a PayOS client instance or an error if initialization fails.

```go
import (
    "context"
    "log"
    "os"

    "github.com/payOSHQ/payos-lib-golang/v2/payos"
)

func main() {
    ctx := context.Background()

    client, err := payos.NewPayOS(&payos.PayOSOptions{
        ClientId:    os.Getenv("PAYOS_CLIENT_ID"),
        ApiKey:      os.Getenv("PAYOS_API_KEY"),
        ChecksumKey: os.Getenv("PAYOS_CHECKSUM_KEY"),
    })
    if err != nil {
        log.Fatal(err)
    }
    // Use the client for further operations
}
```

--------------------------------

### Call usePayOS Hook with Initialized Config

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

How to call the usePayOS hook with the previously initialized configuration to get open() and exit() functions.

```APIDOC
## Call usePayOS Hook with Initialized Config

The `usePayOS` hook returns two functions: `open()` and `exit()`.
```

--------------------------------

### Create Payment Link with Go

Source: https://payos.vn/docs/checkout/quick-start-payos-hosted-page

This Go code snippet sets up an HTTP server to handle payment link creation requests. It initializes the PayOS client with provided keys and defines an endpoint to generate a payment link with order details, redirecting the user to the checkout URL.

```go
package main

import (
	"log"
	"net/http"
	"time"

	"github.com/payOSHQ/payos-lib-golang/v2"
)

var payOSClient *payos.PayOS

func main() {
	// Keep your PayOS key protected by including it by an env variable
	const clientId = "YOUR_CLIENT_ID"
	const apiKey = "YOUR_API_KEY"
	const checksumKey = "YOUR_CHECKSUM_KEY"

	var err error
	payOSClient, err = payos.NewPayOS(&payos.PayOSOptions{
		ClientID:    clientId,
		APIKey:      apiKey,
		ChecksumKey: checksumKey,
	})
	if err != nil {
		log.Fatalf("Failed to create PayOS client: %v", err)
	}

	http.Handle("/", http.FileServer(http.Dir("public")))
	http.HandleFunc("/create-payment-link", createPaymentLink)
	addr := "localhost:3030"
	log.Printf("Listening on %s", addr)
	log.Fatal(http.ListenAndServe(addr, nil))
}

func createPaymentLink(w http.ResponseWriter, r *http.Request) {
	domain := "http://localhost:3030"
	paymentLinkRequest := payos.CreatePaymentLinkRequest{
		OrderCode:   time.Now().UnixNano() / int64(time.Millisecond),
		Amount:      2000,
		Description: "Thanh toan don hang",
		CancelUrl:   domain + "/cancel.html",
		ReturnUrl:   domain + "/success.html",
	}

	paymentLinkResponse, err := payOSClient.PaymentRequests.Create(r.Context(), &paymentLinkRequest)

	if err != nil {
		log.Printf("Create payment link failed: %v", err)
	}

	http.Redirect(w, r, paymentLinkResponse.CheckoutUrl, http.StatusSeeOther)
}
```

--------------------------------

### Run .NET Application

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Command to run the .NET application. After starting the server, you can access the payment link creation interface at http://localhost:3030.

```bash
dotnet run
```

--------------------------------

### Use PayOS usePayOS Hook (JavaScript)

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Call the `usePayOS` hook with the configuration object to get access to the `open()` and `exit()` functions for managing the payment checkout flow.

```javascript
const { open, exit } = PayOSCheckout.usePayOS(config);

// To open the checkout:
// open();

// To close the checkout (if embedded):
// exit();
```

--------------------------------

### Installation

Source: https://payos.vn/docs/sdks/back-end/java

Instructions on how to add the PayOS Java SDK dependency to your Maven or Gradle project.

```APIDOC
## Installation

Add the PayOS Java SDK dependency to your project:

### Maven

```xml
<dependency>
  <groupId>vn.payos</groupId>
  <artifactId>payos-java</artifactId>
  <version>2.0.1</version>
</dependency>
```

### Gradle

```gradle
implementation 'vn.payos:payos-java:2.1.0'
```
```

--------------------------------

### Create Payment Link in Java

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Example of creating a payment link using the PayOS Java SDK. This involves setting up payment details and calling the appropriate SDK method.

```java
// Example payment details (replace with actual data)
String orderCode = "ORDER123";
long amount = 10000; // Amount in cents or smallest currency unit
String description = "Test payment";
String returnUrl = "https://yourdomain.com/success";
String cancelUrl = "https://yourdomain.com/cancel";

// Assuming 'payOS' is an initialized PayOS object
// PaymentLinkResponse response = payOS.createPaymentLink(orderCode, amount, description, returnUrl, cancelUrl);
// String checkoutUrl = response.getCheckoutUrl();
```

--------------------------------

### Run Local Development Server

Source: https://payos.vn/docs/checkout/quick-start-payos-embedded-form

Starts a local PHP development server on port 3030. This command is used to test the integration by serving files from the 'public' directory, allowing you to access your application locally.

```bash
php -S localhost:3030 --docroot=public
```