---
page_source: https://docs.hdfcbank.juspay.in/docs/hypercheckout-mobile-sdk/web/sample-project-setup/backend-setup
page_title: Backend Setup
---


# Generate Keys and Run Sample Project



Merchant must securely generate 2048 bit RSA Public Private Key pair on their servers inside a crypto vault. Merchant must share the Public Key (Key Format-PEM) with the bank during onboarding.

This public-private key pair is crucial for running the project securely.

> **Warning**
> Private key must be securely kept in a crypto vault on the merchant servers. Private key should never flow to the client.




## 1. Generate the Keys



Two sets of Public-Private key pairs are required for encryption. You will generate one such pair and the bank will generate the other pair.

For generating your public-private key, there are two approaches as mentioned below:


### Option 1 Generate the Keys on SmartGateway Dashboard


1. Login to [SmartGateway Dashboard](https://dashboarduat.smartgatewayuat.hdfcbank.com/settings/Security) and navigate to JWT Keys
   
   Login → Payments → Settings → Security → JWT Keys
2. Click on ‘Upload New JWT’ button
   
   ![Image](https://dth95m2xtyv8v.cloudfront.net/tesseract/assets/hypercheckout-mobile-sdk/JWT_Keys.png)
3. Click on ‘I don’t have the JWT Keys, I want to auto generate the keys’ as shown below:
   
   ![Image](https://dth95m2xtyv8v.cloudfront.net/tesseract/assets/hypercheckout-mobile-sdk/GenerateJWTKeys.png)
4. Click on ‘Auto Generate Keys’ button as shown below:
   
   ![Image](https://dth95m2xtyv8v.cloudfront.net/tesseract/assets/hypercheckout-mobile-sdk/Screenshot%202023-12-21%20at%201.47.38%20PM%20(1).png)
5. This will auto-download your Private Key and Bank’s Public Key in your ‘Downloads’ folder as shown below:
   
   ![Image](https://dth95m2xtyv8v.cloudfront.net/tesseract/assets/hypercheckout-mobile-sdk/Screenshot%202024-01-02%20at%204.15.01%20PM.png)
   
   
   
   Please note the description of the downloaded parameters below   
   
   1. **‘privateKey.pem’** _- Y_ our Private Key
   2. **‘key_91e09ab9d5154f569bb2b4ac54d6ee7f.pem’** _-_ Bank’s Public Key
   3. **‘config.json’** _-_ contains file paths of your keys as well as values for Merchant_ID and Payment_Page_Client_ID
6. Bank’s Key Uuid will appear on the SmartGateway Dashboard as shown below:
   
   ![Image](https://dth95m2xtyv8v.cloudfront.net/tesseract/assets/hypercheckout-mobile-sdk/Screenshot%202023-10-31%20at%203.29.08%20PM.png)




### Option 2 Generate the Keys on your Local System


1. **Private Key** : Run the following Command line in your ‘Terminal’ to generate a private key file(private-key.pem):
   
   `openssl genrsa -out private-key.pem 2048`
2. **Public Key** : Run the following Command line in your ‘Terminal’ to generate a public key file(public-key.pem) for the private key file generated in the previous step:
   
   `openssl rsa -in private-key.pem -pubout -out public-key.pem`
3. Upload your Public key(public-key.pem), generated in the previous step, on the [SmartGateway Dashboard](https://dashboarduat.smartgatewayuat.hdfcbank.com/reseller-merchant)
4. Once uploaded, the bank will auto-generate the other Public-Private key pair. Bank's Private key will be stored securely at Bank’s end.
   
   Bank’s Public key will get auto-downloaded in your ‘Downloads’ folder (Example: key_aa**bb.pem file will get auto-downloaded). Bank’s Key Uuid will appear on SmartGateway Dashboard.
   
   ![Image](https://dth95m2xtyv8v.cloudfront.net/tesseract/assets/hypercheckout-mobile-sdk/Screenshot%202023-10-31%20at%203.29.08%20PM.png)




## 2. Run the Sample Project




### Step 2.1 Download the Sample Project file for PHP


Click [here](/repository/downloadGithubFile?repository=https://github.com/juspay/juspay-sdk-integration-demo/archive/refs/heads/expresscheckout-php-sdk.zip) or click on the ‘Download’ button on the top right hand side of the page



#### Code Snippets: -

#### PHP Code Snippet:

```php
# Setup script
- run ```php setup.php``` to install all system dependency

# How to run server
- update configuration in config.json file
- run ```composer run_server``` to run the server
- In browser load the website (localhost:5000)

# How to run standalone service
- update configuration in config.json file
- run ```composer run_app```

# Curl for GET /handleJuspayResponse.php
```
curl --location 'localhost:5000/handleJuspayResponse?order_id=<order_id>'
```
```



### Step 2.2 Input File Paths for Keys in 'config.json' file


**Option 1**  - 

Step 1 : Open the PHP project in your PHP environment and **replace**  the config.json file already present in the project folder with the config.json file downloaded from the dashboard. 

Step 2 : Add your private key (‘**privateKey.pem’)** and Bank’s public key **(‘key_91e09ab9d5154f569bb2b4ac54d6ee7f.pem’ )** to the**** PHP project folder 

**Option 2**  - Open the PHP project in your PHP environment and input the file paths in following keys: 


| Parameter | Description |
|---|---|
| PRIVATE_KEY_PATH | Add the file path for your private key |
| PUBLIC_KEY_PATH  | Add the file path for bank's public key obtained from the dashboard |
| KEY_UUID | Add the Key_Uuid present in the dashboard |
| MERCHANT_ID | Add the Merchant_ID provided by the bank |
| PAYMENT_PAGE_CLIENT_ID | For Sandbox, add 'hdfcmaster' as your client_id |




#### Code Snippets: -

#### PHP Code Snippet:

```php
{"MERCHANT_ID":"YOUR_MERCHANT_ID", "PRIVATE_KEY_PATH":"privateKey.pem","PUBLIC_KEY_PATH":"publicKey.pem","KEY_UUID":"YOUR_KEY_ID", "PAYMENT_PAGE_CLIENT_ID": "YOUR_PAYMENY_PAGE_CLIENT_ID"}
```



### Step 2.3 Install System Dependencies 


Run ‘php setup.php’ to install all system dependencies



#### Code Snippets: -

#### PHP Code Snippet:

```php
# Setup script
- run ```php setup.php``` to install all system dependency

# How to run server
- update configuration in config.json file
- run ```composer run_server``` to run the server
- In browser load the website (localhost:5000)

# How to run standalone service
- update configuration in config.json file
- run ```composer run_app```

# Curl for GET /handleJuspayResponse.php
```
curl --location 'localhost:5000/handleJuspayResponse?order_id=<order_id>'
```
```



### Step 2.4 Run the Server 


1. run **‘composer run_server’**  to run the server
2. In browser load the website ([localhost:5000](http://localhost:5000))



#### Code Snippets: -

#### PHP Code Snippet:

```php
# Setup script
- run ```php setup.php``` to install all system dependency

# How to run server
- update configuration in config.json file
- run ```composer run_server``` to run the server
- In browser load the website (localhost:5000)

# How to run standalone service
- update configuration in config.json file
- run ```composer run_app```

# Curl for GET /handleJuspayResponse.php
```
curl --location 'localhost:5000/handleJuspayResponse?order_id=<order_id>'
```
```



### Step 2.1 Download the Sample Project file for Java


Click [here](/repository/downloadGithubFile?repository=https://github.com/juspay/juspay-sdk-integration-demo/archive/refs/heads/expresscheckout-java-sdk.zip) or click on the ‘Download’ button on the top right hand side of the page



#### Code Snippets: -

#### Java Code Snippet:

```java
{
  "MERCHANT_ID":"YOUR_MERCHANT_ID",
  "PRIVATE_KEY_PATH":"~/Desktop/JuspayBackendKit/src/main/resources/private-key.pem",
  "PUBLIC_KEY_PATH":"~/Desktop/JuspayBackendKit/src/main/resources/public-key.pem",
  "KEY_UUID":"YOUR_KEY_ID",
  "PAYMENT_PAGE_CLIENT_ID": "YOUR_PAYMENY_PAGE_CLIENT_ID"
}
```



### Step 2.2 Input File Paths for Keys in 'config.json' file


**Option 1**  - 

Step 1 : Open the Java project in your Java environment and **replace**  the config.json file already present in the project folder **(JuspayBackendKit/src/main/resources)**  with the config.json file downloaded from the dashboard 

Step 2 : Add your private key (‘**privateKey.pem’)** and Bank’s public key **(‘key_91e09ab9d5154f569bb2b4ac54d6ee7f.pem’ )** to the**** Java project folder **(JuspayBackendKit/src/main/resources)** 

**Option 2**  - Open the Java project in your Java environment and input the file paths in following keys: 


| Parameter | Description |
|---|---|
| PRIVATE_KEY_PATH | Add the absolute file path for your private key |
| PUBLIC_KEY_PATH | Add the absolute file path for bank's public key obtained from the dashboard |
| KEY_UUID | Add the Key_Uuid present in the dashboard |
| MERCHANT_ID | Add the Merchant_ID provided by the bank |
| PAYMENT_PAGE_CLIENT_ID | For Sandbox, add 'hdfcmaster' as your client_id |




#### Code Snippets: -

#### Java Code Snippet:

```java
{
  "MERCHANT_ID":"YOUR_MERCHANT_ID",
  "PRIVATE_KEY_PATH":"~/Desktop/JuspayBackendKit/src/main/resources/private-key.pem",
  "PUBLIC_KEY_PATH":"~/Desktop/JuspayBackendKit/src/main/resources/public-key.pem",
  "KEY_UUID":"YOUR_KEY_ID",
  "PAYMENT_PAGE_CLIENT_ID": "YOUR_PAYMENY_PAGE_CLIENT_ID"
}
```



### Step 2.3 Check the prerequisites


Check if the below mentioned prerequisites are in place:

* Java sdk >= 8
* Maven
* JAVA_HOME path configured



#### Code Snippets: -

#### Java Code Snippet:

```java
# Juspay Sample App
Sample app for juspay java integration using expresscheckout-java-sdk

# Prerequisites
- Java sdk >= 8
- Maven
- JAVA_HOME path configured

# Setup Configurations
Place your config.json file in src/main/resources folder. Here's the sample for config.json file.
```json
{
  "MERCHANT_ID":"YOUR_MERCHANT_ID",
  "PRIVATE_KEY_PATH":"~/Desktop/JuspayBackendKit/src/main/resources/private-key.pem",
  "PUBLIC_KEY_PATH":"~/Desktop/JuspayBackendKit/src/main/resources/public-key.pem",
  "KEY_UUID":"YOUR_KEY_UUID",
  "PAYMENT_PAGE_CLIENT_ID": "YOUR_PAYMENT_PAGE_CLIENT_ID"
}
```
You can skip giving `PUBLIC_KEY_PATH` and `PRIVATE_KEY_PATH` and add `private-key.pem` and `public-key.pem` inside resources' folder.
Note:- key file path has to be absolute.

## Run Application
The app is made using Servlets. Hence, multiple ways to run the application.

[//]: # (block:start:run-server)
### Quick run using `setup.sh`
```bash
chmod +x ./setup.sh
./setup.sh
```

### Quick run using jetty
```bash
mvn clean install
mvn clean package
mvn jetty:run
```
[//]: # (block:end:run-server)

# Want to add inside your own project (Servlet based project)
Please find `in.juspaybackendkit` package and copy it to your own setup. Now that we have added skd code in the project we'll configure web.xml
Add this in your web.xml file. It may defer depending upon your own setup.

```xml
<listener>
        <listener-class>in.juspaybackendkit.JuspayConfig</listener-class>
</listener>
<servlet>
    <servlet-name>InitiateJuspayPayment</servlet-name>
    <servlet-class>in.juspaybackendkit.InitiateJuspayPayment</servlet-class>
</servlet>
<servlet>
    <servlet-name>HandleJuspayResponse</servlet-name>
    <servlet-class>in.juspaybackendkit.HandleJuspayResponse</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>InitiateJuspayPayment</servlet-name>
    <url-pattern>/initiateJuspayPayment</url-pattern>
</servlet-mapping>
<servlet-mapping>
    <servlet-name>HandleJuspayResponse</servlet-name>
    <url-pattern>/handleJuspayResponse</url-pattern>
</servlet-mapping>
```

Add dependencies to your project.

```xml
<dependency>
  <groupId>in.juspay</groupId>
  <artifactId>expresscheckout</artifactId>
  <version>1.3.3</version>
</dependency>
<dependency>
  <groupId>javax.xml.bind</groupId>
  <artifactId>jaxb-api</artifactId>
  <version>2.4.0-b180830.0359</version>
</dependency>
```
```



### Step 2.4 Run the server


For Linux systems, quick run using ‘setup.sh’ file

`chmod +x ./setup.sh`

`./setup.sh`

For other systems, use Jetty to run the following:

`mvn clean install`

`mvn clean package`

`mvn jetty:run`



#### Code Snippets: -

#### Java Code Snippet:

```java
# Juspay Sample App
Sample app for juspay java integration using expresscheckout-java-sdk

# Prerequisites
- Java sdk >= 8
- Maven
- JAVA_HOME path configured

# Setup Configurations
Place your config.json file in src/main/resources folder. Here's the sample for config.json file.
```json
{
  "MERCHANT_ID":"YOUR_MERCHANT_ID",
  "PRIVATE_KEY_PATH":"~/Desktop/JuspayBackendKit/src/main/resources/private-key.pem",
  "PUBLIC_KEY_PATH":"~/Desktop/JuspayBackendKit/src/main/resources/public-key.pem",
  "KEY_UUID":"YOUR_KEY_UUID",
  "PAYMENT_PAGE_CLIENT_ID": "YOUR_PAYMENT_PAGE_CLIENT_ID"
}
```
You can skip giving `PUBLIC_KEY_PATH` and `PRIVATE_KEY_PATH` and add `private-key.pem` and `public-key.pem` inside resources' folder.
Note:- key file path has to be absolute.

## Run Application
The app is made using Servlets. Hence, multiple ways to run the application.

[//]: # (block:start:run-server)
### Quick run using `setup.sh`
```bash
chmod +x ./setup.sh
./setup.sh
```

### Quick run using jetty
```bash
mvn clean install
mvn clean package
mvn jetty:run
```
[//]: # (block:end:run-server)

# Want to add inside your own project (Servlet based project)
Please find `in.juspaybackendkit` package and copy it to your own setup. Now that we have added skd code in the project we'll configure web.xml
Add this in your web.xml file. It may defer depending upon your own setup.

```xml
<listener>
        <listener-class>in.juspaybackendkit.JuspayConfig</listener-class>
</listener>
<servlet>
    <servlet-name>InitiateJuspayPayment</servlet-name>
    <servlet-class>in.juspaybackendkit.InitiateJuspayPayment</servlet-class>
</servlet>
<servlet>
    <servlet-name>HandleJuspayResponse</servlet-name>
    <servlet-class>in.juspaybackendkit.HandleJuspayResponse</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>InitiateJuspayPayment</servlet-name>
    <url-pattern>/initiateJuspayPayment</url-pattern>
</servlet-mapping>
<servlet-mapping>
    <servlet-name>HandleJuspayResponse</servlet-name>
    <url-pattern>/handleJuspayResponse</url-pattern>
</servlet-mapping>
```

Add dependencies to your project.

```xml
<dependency>
  <groupId>in.juspay</groupId>
  <artifactId>expresscheckout</artifactId>
  <version>1.3.3</version>
</dependency>
<dependency>
  <groupId>javax.xml.bind</groupId>
  <artifactId>jaxb-api</artifactId>
  <version>2.4.0-b180830.0359</version>
</dependency>
```
```



### Step 2.1 Download the Sample Project file for .NET


Click [here](/repository/downloadGithubFile?repository=https://github.com/juspay/juspay-sdk-integration-demo/archive/refs/heads/expresscheckout-dotnet-sdk.zip) or on the ‘Download’ button on the top right hand side of the page



#### Code Snippets: -

#### .NET Code Snippet:

```.net
# How to run server
- update configuration in config.json file
- run ```dotnet run -f <framework>``` to run the server
- In browser load the website (localhost:5000)
- Option for -f net7.0,net6.0, netcoreapp3.1, netcoreapp3.0 and net5.0

# Curl for GET /handleJuspayResponse.php
```
curl --location 'localhost:5000/handleJuspayResponse?order_id=<order_id>'
```

```



### Step 2.2 Input File Paths for Keys in 'config.json' file 


**Option 1**  - 

Step 1 : Open the .NET project in your .NET environment and **replace**  the config.json file already present in the project folder (expresscheckout-dotnet-framework-sdk) with the config.json file downloaded from the dashboard 

Step 2 : Add your private key (‘**privateKey.pem’)** and Bank’s public key **(‘key_91e09ab9d5154f569bb2b4ac54d6ee7f.pem’ )** to the**.NET** project folder (expresscheckout-dotnet-framework-sdk)

**Option 2**  - Open the .NET project in your .NET environment and input the file paths in following keys: 


| Parameter | Description |
|---|---|
| PRIVATE_KEY_PATH | Add the absolute file path for your private key |
| PUBLIC_KEY_PATH | Add the absolute file path for bank's public key obtained from the dashboard |
| KEY_UUID | Add the Key_Uuid present in the dashboard |
| MERCHANT_ID | Add the Merchant_ID provided by the bank |
| PAYMENT_PAGE_CLIENT_ID | For Sandbox, add 'hdfcmaster' as your client_id |




#### Code Snippets: -

#### .NET Code Snippet:

```.net
{"MERCHANT_ID":"YOUR_MERCHANT_ID", "PRIVATE_KEY_PATH":"privateKey.pem","PUBLIC_KEY_PATH":"publicKey.pem","KEY_UUID":"YOUR_KEY_ID", "PAYMENT_PAGE_CLIENT_ID": "YOUR_PAYMENY_PAGE_CLIENT_ID"}
```



### Step 2.3 Update your .NET version


Run the following command with your .NET version (net7.0/net6.0/net5.0):

`dotnet run -f net7.0`



#### Code Snippets: -

#### .NET Code Snippet:

```.net
# How to run server
- update configuration in config.json file
- run ```dotnet run -f <framework>``` to run the server
- In browser load the website (localhost:5000)
- Option for -f net7.0,net6.0, netcoreapp3.1, netcoreapp3.0 and net5.0

# Curl for GET /handleJuspayResponse.php
```
curl --location 'localhost:5000/handleJuspayResponse?order_id=<order_id>'
```

```



### Step 2.4 Test the payment flow


Load the website ([localhost:5000](http://localhost:5000)) on any browser to test the payment flow



#### Code Snippets: -

#### .NET Code Snippet:

```.net
# How to run server
- update configuration in config.json file
- run ```dotnet run -f <framework>``` to run the server
- In browser load the website (localhost:5000)
- Option for -f net7.0,net6.0, netcoreapp3.1, netcoreapp3.0 and net5.0

# Curl for GET /handleJuspayResponse.php
```
curl --location 'localhost:5000/handleJuspayResponse?order_id=<order_id>'
```

```



### NOTE: Versions supported:


1.NetFramework :- 4.6.1 and above2.netCore :- 3.0 and above3 .net:- 5.0 and above



#### Code Snippets: -

#### .NET Code Snippet:

```.net
# How to run server
- update configuration in config.json file
- run ```dotnet run -f <framework>``` to run the server
- In browser load the website (localhost:5000)
- Option for -f net7.0,net6.0, netcoreapp3.1, netcoreapp3.0 and net5.0

# Curl for GET /handleJuspayResponse.php
```
curl --location 'localhost:5000/handleJuspayResponse?order_id=<order_id>'
```

```



### Step 2.1 Download the Sample Project file for Node JS


Click [here](/repository/downloadGithubFile?repository=https://github.com/juspay/juspay-sdk-integration-demo/archive/refs/heads/expresscheckout-dotnet-sdk.zip) or on the ‘Download’ button on the top right hand side of the page



#### Code Snippets: -

#### Node JS Code Snippet:

```node js

# Setup script
- run ```npm i``` to install all system dependency

# How to run server
- update configuration in config.json file
- run ```npm start``` to run the server
- In browser load the website (localhost:5000)

# How to run standalone service
- update configuration in config.json file
- run ```npm install```
- run ```npm start```

```



### Step 2.2 Input File Paths for Keys in 'config.json' file 


**Option 1**  - 

Step 1 : Open the Node JS project in your Node JS environment and **replace**  the config.json file already present in the project folder  with the config.json file downloaded from the dashboard 

Step 2 : Add your private key (‘**privateKey.pem’)** and Bank’s public key **(‘key_91e09ab9d5154f569bb2b4ac54d6ee7f.pem’ )** to the**Node JS** project folder (expresscheckout-dotnet-framework-sdk)

**Option 2**  - Open the Node JS project in your Node JS environment and input the file paths in following keys: 


| Parameter | Description |
|---|---|
| PRIVATE_KEY_PATH | Add the absolute file path for your private key |
| PUBLIC_KEY_PATH | Add the absolute file path for bank's public key obtained from the dashboard |
| KEY_UUID | Add the Key_Uuid present in the dashboard |
| MERCHANT_ID | Add the Merchant_ID provided by the bank |
| PAYMENT_PAGE_CLIENT_ID | For Sandbox, add 'hdfcmaster' as your client_id |




#### Code Snippets: -

#### Node JS Code Snippet:

```node js
{
    "MERCHANT_ID":"YOUR_MERCHANT_ID",
    "PRIVATE_KEY_PATH":"privateKey.pem",
    "PUBLIC_KEY_PATH":"public-key.pem",
    "KEY_UUID":"YOUR_KEY_ID",
    "PAYMENT_PAGE_CLIENT_ID": "YOUR_PAYMENY_PAGE_CLIENT_ID"
  }
```



### Step 2.3 Install System Dependencies


Run **‘npm i’**  to install all the system dependencies



#### Code Snippets: -

#### Node JS Code Snippet:

```node js
{
    "MERCHANT_ID":"YOUR_MERCHANT_ID",
    "PRIVATE_KEY_PATH":"privateKey.pem",
    "PUBLIC_KEY_PATH":"public-key.pem",
    "KEY_UUID":"YOUR_KEY_ID",
    "PAYMENT_PAGE_CLIENT_ID": "YOUR_PAYMENY_PAGE_CLIENT_ID"
  }
```



### Step 2.4 Run the Server


1. run **‘npm start’**  to run the server
2. In browser load the website ([localhost:5000](http://localhost:5000))



#### Code Snippets: -

#### Node JS Code Snippet:

```node js
{
    "MERCHANT_ID":"YOUR_MERCHANT_ID",
    "PRIVATE_KEY_PATH":"privateKey.pem",
    "PUBLIC_KEY_PATH":"public-key.pem",
    "KEY_UUID":"YOUR_KEY_ID",
    "PAYMENT_PAGE_CLIENT_ID": "YOUR_PAYMENY_PAGE_CLIENT_ID"
  }
```