Connect to Backend API

Connecting GDS-compliant views to backend APIs transforms static forms into fully functional web applications. This final step completes the migration from legacy desktop application to modern web-based solution with secure data integration.

flowchart TD
    A["🎨 GDS-Compliant Views"] --> B["🔍 API Analysis & Preparation"]
    C["🔌 Backend API Endpoints"] --> B
    B --> D["🔐 Setup Authentication & Security"]
    D --> E["🤖 Implement API Integration"]
    E --> F["🧪 Testing & Validation"]
    F --> G{"Integration Complete?"}
    G -->|No| H["🔄 Refine Integration"]
    G -->|Yes| I["🚀 Deploy & Monitor"]
    I --> J["✅ Fully Functional Web Application"]
    H --> E

    classDef input fill:#ffebee,stroke:#c62828,stroke-width:2px
    classDef process fill:#e3f2fd,stroke:#1976d2,stroke-width:2px
    classDef security fill:#fff3e0,stroke:#f57c00,stroke-width:2px
    classDef ai fill:#f3e5f5,stroke:#7b1fa2,stroke-width:2px
    classDef testing fill:#fce4ec,stroke:#ad1457,stroke-width:2px
    classDef decision fill:#ffeb3b,stroke:#f57f17,stroke-width:2px
    classDef deployment fill:#e0f2f1,stroke:#00695c,stroke-width:2px
    classDef output fill:#e8f5e8,stroke:#2e7d32,stroke-width:2px

    class A,C input
    class B process
    class D security
    class E,H ai
    class F testing
    class G decision
    class I deployment
    class J output

Prerequisites

• Completed GDS-compliant views from the previous step
• Backend API endpoints available (from database migration pathway)
• API documentation or OpenAPI specification
• Understanding of authentication and authorization requirements
• Development environment configured for API integration

Key Activities

1. Analyze and Prepare API Integration

Understand your backend systems and plan the integration approach:

• Review API documentation: Study endpoint specifications and requirements
• Map form fields: Connect to API data structures and identify transformations
• Plan authentication: Set up mechanisms (OAuth, JWT, API keys)
• Identify data validation: Define requirements and error handling needs

2. Implement Secure API Connections

Connect your GDS views to backend services using AI assistance:

• Use the Connect to Backend API guidance: Ensure consistent implementation
• Implement authentication: Set up token management and security
• Set up data fetching: Create GET requests with loading states and caching
• Connect form submissions: Build POST/PUT requests with validation and user feedback
• Handle errors gracefully: Implement GDS-compliant error messages

Mock API Development (If Backend Not Ready)

If backend APIs are still in development, use the OpenAPI specification from the API section to create a mock environment:

• Generate Mockoon environment: Create from OpenAPI specification for immediate development
• Create realistic test data: Match expected API responses accurately
• Implement authentication mocking: Test secure flows without real backend
• Use mock endpoints: Enable frontend development and testing
• Switch to real APIs: Transition seamlessly once backend is available

3. Test and Validate Integration

Ensure reliable API integration through comprehensive testing:

• Integration testing: Test all endpoints, data flow, and authentication
• Performance testing: Validate with realistic data volumes and concurrent users
• Error scenario testing: Test network errors, validation failures, and edge cases
• User acceptance testing: Verify end-to-end workflows match legacy functionality

Common Challenges and Solutions

• Authentication Failures: Implement proper token management and error handling. Provide clear user feedback for authentication issues.
• Data Mapping Issues: Carefully map form fields to API structures. Use data transformation layers where needed.
• Performance Problems: Implement caching strategies, progressive loading, and optimize API calls.

Success Criteria

API integration is complete when:

• ✅ All forms connect securely to backend APIs
• ✅ Authentication and authorization work correctly
• ✅ Data flows properly between frontend and backend
• ✅ Error handling provides clear user feedback
• ✅ Performance meets user expectations
• ✅ End-to-end workflows function as required
• ✅ Integration testing passes all scenarios

Next Steps

This completes the frontend migration pathway. Your legacy MS Access forms have been successfully transformed into a modern, accessible web application with secure backend integration.

This step is part of the DEFRA AI Legacy Modernisation Playbook.