Pay-NP 🇳🇵

Pay-NP is a unified Go SDK for integrating with all major payment providers in Nepal. This is your one-stop solution for handling digital payments in the Nepalese market.

🚀 Features

• Multiple Payment Providers: Unified interface for eSewa, ConnectIPS (NCHL), and more
• Type-Safe: Strongly typed API for all payment operations
• Secure: Built-in signature generation and verification
• Easy Integration: Simple and intuitive API design
• Well-Tested: Comprehensive test coverage
• Production Ready: Used in production environments

📦 Supported Payment Providers

Provider	Status	Features
eSewa	✅ Supported	Signature generation, Payment verification, HMAC-SHA256
ConnectIPS (NCHL/CIPS)	✅ Supported	Transaction validation, Transaction details, RSA digital signatures

🔧 Installation

go get github.com/mukezhz/pay-np

📚 Usage

eSewa Integration

eSewa is one of Nepal's leading digital payment platforms. Here's how to integrate it:

package main

import (
    "fmt"
    "github.com/mukezhz/pay-np/esewa"
)

func main() {
    // Your eSewa secret key
    secret := "your_esewa_secret_key"
    
    // Create payment payload
    payload := &esewa.EsewaPayload{
        Amount:                "100",
        TaxAmount:             "13",
        TotalAmount:           "113",
        TransactionUUID:       "unique-transaction-id",
        ProductServiceCharge:  "0",
        ProductDeliveryCharge: "0",
        ProductCode:           "EPAYTEST",
        SuccessURL:            "https://yoursite.com/success",
        FailureURL:            "https://yoursite.com/failure",
        SignedFieldNames:      "total_amount,transaction_uuid,product_code",
    }
    
    // Create eSewa client
    client, err := esewa.New(secret, payload)
    if err != nil {
        panic(err)
    }
    
    // Generate signature for payment request
    signature, err := client.GenerateSignature()
    if err != nil {
        panic(err)
    }
    
    fmt.Println("Signature:", signature)
    
    // Verify payment response (after payment completion)
    err = client.VerifySignature(base64EncodedResponse)
    if err != nil {
        fmt.Println("Payment verification failed:", err)
        return
    }
    
    fmt.Println("Payment verified successfully!")
    fmt.Println("Transaction Code:", client.ReponsePayload.TransactionCode)
    fmt.Println("Status:", client.ReponsePayload.Status)
}

ConnectIPS (NCHL/CIPS) Integration

ConnectIPS is Nepal's interbank payment gateway. Here's how to use it:

package main

import (
    "fmt"
    "github.com/mukezhz/pay-np/nchl"
    "github.com/mukezhz/pay-np/utils"
)

func main() {
    // Create CIPS client
    client := nchl.New("https://uat.connectips.com")
    
    // Load your PFX certificate
    privateKey, err := client.LoadPrivateKeyFromPFX("path/to/cert.pfx", "password")
    if err != nil {
        panic(err)
    }
    
    // Generate digital signature
    payload := "your_payload_string"
    signature, err := client.GenerateDigitalSignatureWithRSA(utils.GenerateDigitalSignatureWithRSAParams{
        PfxCertPath: "path/to/cert.pfx",
        Password:    "password",
        Payload:     payload,
        PrivKey:     privateKey,
    })
    if err != nil {
        panic(err)
    }
    
    // Validate transaction
    req := nchl.CIPSJSONRequest{
        MerchantID:  12345,
        AppID:       "YOUR_APP_ID",
        TxnAmount:   "1000",
        ReferenceID: "unique-ref-id",
        Token:       "your_token",
    }
    
    resp, statusCode, err := client.ValidateTxn(req, "Bearer "+signature)
    if err != nil {
        panic(err)
    }
    
    fmt.Printf("Status: %s, Code: %d\n", resp.Status, statusCode)
    
    // Get transaction details
    details, statusCode, err := client.GetTxnDetail(req, "Bearer "+signature)
    if err != nil {
        panic(err)
    }
    
    fmt.Printf("Transaction ID: %d\n", details.TxnID)
    fmt.Printf("Amount: %.2f\n", details.TxnAmount)
}

🏗️ Project Structure

pay-np/
├── esewa/              # eSewa payment integration
│   ├── esewa_client.go # Client implementation
│   ├── types.go        # Data structures
│   └── README.md       # eSewa-specific documentation
├── nchl/               # ConnectIPS (NCHL) integration
│   ├── cips_client.go  # CIPS client implementation
│   └── types.go        # Data structures
├── errorz/             # Custom error types
│   ├── esewa_error.go  # eSewa-specific errors
│   └── cips_error.go   # CIPS-specific errors
├── utils/              # Utility functions
│   └── crypto.go       # Cryptographic utilities (HMAC, RSA, SHA256)
└── esewa_test.go       # Test cases

🔐 Security

This SDK implements industry-standard security practices:

• HMAC-SHA256 for eSewa signature generation and verification
• RSA Digital Signatures with PKCS#1 v1.5 for ConnectIPS
• Base64 Encoding for secure data transmission
• Certificate-based Authentication for ConnectIPS using PFX/PKCS12

🧪 Testing

Run the test suite:

go test ./...

Run specific tests:

go test esewa_test.go

🛠️ Error Handling

The SDK provides comprehensive error handling with custom error types:

// eSewa errors
errorz.ErrEsewaTotalAmount          // Missing total amount
errorz.ErrEsewaTransactionUUID      // Missing transaction UUID
errorz.ErrEsewaProductCode          // Missing product code
errorz.ErrEsewaInvalidDataForSignature  // Invalid signature data

// CIPS errors
errorz.ErrCIPSFailedToReadPFX       // Failed to read PFX certificate
errorz.ErrCIPSFailedToDecodePFX     // Failed to decode PFX
errorz.ErrCIPSPrivateKeyNotRSA      // Private key is not RSA
errorz.ErrCIPSSigningFailed         // Signature generation failed

🌐 API Endpoints

eSewa

• Production: https://epay.esewa.com.np/api/epay/
• Testing: https://uat.esewa.com.np/epay/

ConnectIPS (NCHL)

• Production: https://connectips.com/
• UAT: https://uat.connectips.com/

📋 Requirements

• Go 1.24 or higher
• Valid merchant accounts with respective payment providers
• For ConnectIPS: PFX certificate from your bank

🤝 Contributing

Contributions are welcome! If you'd like to add support for more Nepalese payment providers or improve existing implementations:

1. Fork the repository
2. Create your feature branch (git checkout -b feature/new-provider)
3. Commit your changes (git commit -am 'Add support for XYZ payment provider')
4. Push to the branch (git push origin feature/new-provider)
5. Open a Pull Request

📝 Roadmap

• Add Khalti payment integration
• Add IME Pay integration
• Add Prabhu Pay integration
• Add webhook handling utilities
• Add payment reconciliation tools
• Improve documentation with more examples
• Add integration tests with mock servers

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

💬 Support

If you encounter any issues or have questions:

• Open an issue on GitHub
• Check the documentation in respective provider directories
• Review the test files for usage examples

🙏 Acknowledgments

• eSewa for their payment gateway services
• NCHL (National Clearing and Settlement Limited) for ConnectIPS
• The Go community for excellent cryptographic libraries

⚠️ Disclaimer

This is an unofficial SDK. Please ensure you comply with all terms and conditions of the respective payment providers. Always test thoroughly in sandbox/UAT environments before going to production.

---

Made with ❤️ for the Nepalese developer community