# 📖 Documentation Index

Welcome to the Mercury UPI PSP Platform documentation. This index provides quick access to all documentation organized by category.

## 🚀 Quick Start

**New to the platform?** Start here:
1. [Project Configuration](guides/PROJECT_CONFIG.md) - Initial setup
2. [API Overview](api/API_README.md) - Understanding the APIs
3. [Testing Guide](guides/TESTING_GUIDE.md) - Running tests
4. [Contributing Guidelines](guides/CONTRIBUTING.md) - Development workflow

## 📚 Documentation Categories

### 🔗 API Documentation
| Document | Description |
|----------|-------------|
| [API README](api/API_README.md) | API overview and getting started guide |
| [Complete UPI API Documentation](api/COMPLETE_UPI_API_DOCUMENTATION.md) | Comprehensive API reference with examples |

### 🏗️ Implementation Guides
| Document | Description |
|----------|-------------|
| [Implementation Plan](implementation/IMPLEMENTATION_PLAN.md) | Original implementation strategy |
| [Implementation Summary](implementation/IMPLEMENTATION_SUMMARY.md) | High-level implementation overview |
| [International ReqPay Implementation](implementation/INTERNATIONAL_REQPAY_IMPLEMENTATION.md) | International payment flows |
| [Phase 5B Real Partners](implementation/PHASE_5B_REAL_PARTNERS.md) | Partner integration details |
| [UPI PSP Implementation Summary](implementation/UPI_PSP_IMPLEMENTATION_SUMMARY.md) | Complete UPI PSP overview |
| [**🆕 NPCI UPI Complete Implementation**](implementation/NPCI_UPI_COMPLETE_IMPLEMENTATION.md) | **Complete NPCI implementation with QR validation and heartbeat** |

### 📋 Setup & Development Guides
| Document | Description |
|----------|-------------|
| [Contributing Guidelines](guides/CONTRIBUTING.md) | How to contribute to the project |
| [Testing Guide](guides/TESTING_GUIDE.md) | Comprehensive testing procedures |
| [Postman Collection Guide](guides/POSTMAN_COLLECTION_GUIDE.md) | API testing with Postman |
| [Project Configuration](guides/PROJECT_CONFIG.md) | Environment and project setup |
| [TideWave Setup](guides/TIDEWAVE_SETUP.md) | TideWave integration configuration |
| [NPCI Rules Gap Analysis](guides/NPCI_RULES_GAP_ANALYSIS.md) | NPCI compliance analysis |
| [UPI Specification Document](guides/UPI-Specififcation-Document.md) | Official UPI specification reference |

## 🔍 Quick Reference

### 🏛️ NPCI UPI APIs
- **ReqValQR / RespValQR**: QR code validation
- **ReqPay / RespPay**: Payment processing
- **ReqMandate / RespMandate**: Recurring payments
- **ReqCollect / RespCollect**: Payment collection
- **ReqBalEnq / RespBalEnq**: Balance inquiry
- **ReqTxnStatus / RespTxnStatus**: Transaction status
- **ReqComplaint / RespComplaint**: Complaint handling
- **ReqHBT / RespHBT**: Health check

### 🌍 International Corridors
- **SGD-INR**: Singapore to India
- **USD-INR**: USA to India  
- **AED-INR**: UAE to India

### 🔧 Key Technologies
- **Backend**: Elixir/Phoenix, OTP
- **Database**: MySQL with Ecto
- **Frontend**: Phoenix LiveView, DaisyUI
- **Integration**: REST APIs, XML processing
- **Monitoring**: Telemetry, Custom metrics

## 🆘 Support & Troubleshooting

### Common Issues
1. **Setup Problems**: Check [Project Configuration](guides/PROJECT_CONFIG.md)
2. **API Errors**: Refer to [API Documentation](api/COMPLETE_UPI_API_DOCUMENTATION.md)
3. **Testing Issues**: Follow [Testing Guide](guides/TESTING_GUIDE.md)
4. **Integration Problems**: Review [TideWave Setup](guides/TIDEWAVE_SETUP.md)

### Getting Help
- **Documentation Issues**: Check this index for the right document
- **Code Issues**: Follow [Contributing Guidelines](guides/CONTRIBUTING.md)
- **API Questions**: Start with [API README](api/API_README.md)

## 🎯 Development Workflow

1. **Setup**: Follow [Project Configuration](guides/PROJECT_CONFIG.md)
2. **Development**: Follow [Contributing Guidelines](guides/CONTRIBUTING.md)
3. **Testing**: Use [Testing Guide](guides/TESTING_GUIDE.md) and `../manual_testing/`
4. **Integration**: Refer to relevant implementation guides
5. **Deployment**: Follow production setup procedures

---

**📍 Navigation**: [← Back to Project Root](../README.md) | [Manual Testing →](../manual_testing/README.md)