# M-Pesa Integration Roadmap for LendCore

Based on my review of the official M-Pesa Daraja API documentation, here's a comprehensive roadmap for implementing M-Pesa integration in LendCore (your Laravel loan management system). This roadmap focuses on C2B (for receiving loan repayments) and B2C (for disbursing approved loans), as these are the core payment flows for a loan management platform.

## Phase 1: Planning and Setup (1-2 days)
**Objective:** Establish foundation and prerequisites

**Tasks:**
1. **Requirements Analysis**
   - Confirm C2B for loan repayments (customers paying to business)
   - Confirm B2C for loan disbursements (business paying to customers)
   - Identify callback URL requirements (must be HTTPS in production)
   - Review security requirements (IP whitelisting, signature validation)

2. **Daraja Account Setup**
   - Create Safaricom Developer Portal account
   - Create sandbox application with C2B and B2C products
   - Obtain Consumer Key and Consumer Secret
   - Note sandbox vs production endpoint differences

3. **Environment Configuration**
   - Add M-Pesa credentials to `.env` file
   - Set up ngrok tunnel for local development callbacks
   - Configure SESSION_DOMAIN for production

**Deliverables:**
- Sandbox app credentials
- ngrok tunnel configured
- Updated `.env` with M-Pesa settings

## Phase 2: Authentication & Core Services (2-3 days)
**Objective:** Implement OAuth authentication and base API service

**Tasks:**
1. **OAuth Token Service**
   - Create `MpesaAuthService` for token generation
   - Implement token caching (tokens valid for 1 hour)
   - Handle token refresh automatically

2. **Base API Service**
   - Create `MpesaApiService` with HTTP client
   - Implement request/response logging
   - Add error handling for common API errors

3. **Security Implementation**
   - Add IP whitelist middleware for callback endpoints
   - Implement request signature validation (if required)
   - Add rate limiting for API calls

**Deliverables:**
- `app/Services/MpesaAuthService.php`
- `app/Services/MpesaApiService.php`
- `app/Http/Middleware/MpesaSecurityMiddleware.php`

## Phase 3: C2B Implementation (3-4 days)
**Objective:** Enable receiving payments from customers

**Tasks:**
1. **URL Registration**
   - Implement C2B URL registration endpoint
   - Register validation and confirmation URLs
   - Handle registration responses and errors

2. **Validation Callback Handler**
   - Create `/api/c2b/validation` endpoint
   - Implement validation logic (optional, but recommended)
   - Return appropriate ResultCode responses

3. **Confirmation Callback Handler**
   - Create `/api/c2b/confirmation` endpoint
   - Parse C2B payload (TransactionType, TransID, TransAmount, etc.)
   - Map BillRefNumber to loan ID (e.g., "LN-1001" → loan_id: 1001)
   - Update transaction and repayment records
   - Handle idempotency (duplicate callbacks)

4. **Transaction Processing**
   - Link payments to existing transactions
   - Update repayment status (pending → completed)
   - Update loan status based on payment progress
   - Send notifications to users

**Deliverables:**
- `app/Http/Controllers/Api/C2bController.php`
- Updated transaction/repayment processing logic
- Audit logging for all C2B operations

## Phase 4: B2C Implementation (3-4 days)
**Objective:** Enable disbursing funds to customers

**Tasks:**
1. **Security Credential Setup**
   - Implement password encryption using public certificate
   - Create encrypted SecurityCredential for API calls
   - Handle certificate management

2. **Disbursement Request**
   - Create B2C payment request endpoint
   - Implement required parameters (OriginatorConversationID, PartyA, PartyB, etc.)
   - Handle different CommandID types (BusinessPayment, etc.)

3. **Result Callback Handler**
   - Create `/api/b2c/result` endpoint
   - Parse B2C result payload (ResultCode, TransactionID, etc.)
   - Update transaction status based on ResultCode
   - Handle successful disbursements (activate loans)

4. **Timeout Callback Handler**
   - Create `/api/b2c/timeout` endpoint
   - Handle queued transaction timeouts
   - Implement retry logic or manual intervention

**Deliverables:**
- `app/Http/Controllers/Api/B2cController.php`
- `app/Services/MpesaSecurityService.php` (for credential encryption)
- Loan disbursement workflow integration

## Phase 5: STK Push Implementation (2-3 days) - Optional
**Objective:** Enable customer-initiated payments via USSD

**Tasks:**
1. **STK Push Request**
   - Implement M-Pesa Express API calls
   - Handle passkey generation and timestamp
   - Create payment initiation endpoints

2. **STK Callback Handler**
   - Create `/api/stk/callback` endpoint
   - Parse STK callback payloads
   - Update transactions based on CheckoutRequestID

**Deliverables:**
- `app/Http/Controllers/Api/StkController.php`
- STK push integration for loan applications

## Phase 6: Testing & Validation (2-3 days)
**Objective:** Ensure reliable operation across scenarios

**Tasks:**
1. **Simulator Testing**
   - Use Daraja simulator for C2B/B2C/STK flows
   - Test success and failure scenarios
   - Validate callback handling

2. **Postman Testing**
   - Import Daraja Postman collection
   - Test all endpoints with various payloads
   - Document test cases

3. **Integration Testing**
   - Create PHPUnit tests for callback controllers
   - Test loan status updates
   - Test idempotency and error handling

4. **Edge Case Testing**
   - Network timeouts
   - Invalid payloads
   - Duplicate callbacks
   - Amount mismatches

**Deliverables:**
- Comprehensive test suite
- Test documentation
- Error scenario handling

## Phase 7: Production Deployment (1-2 days)
**Objective:** Go live with production environment

**Tasks:**
1. **Live Account Setup**
   - Apply for live Paybill/Till number with B2C capabilities
   - Create Business Administrator and API users
   - Set up M-Pesa Organization Portal access

2. **Production Configuration**
   - Update endpoints to production URLs
   - Register production callback URLs
   - Update credentials in production `.env`

3. **Go-Live Process**
   - Submit go-live request on Daraja portal
   - Wait for approval and production credentials
   - Test with real shortcodes

4. **Monitoring Setup**
   - Implement callback failure alerts
   - Set up transaction monitoring
   - Configure error logging

**Deliverables:**
- Production-ready configuration
- Monitoring and alerting setup
- Go-live documentation

## Phase 8: Additional Features (1-2 days) - Optional
**Objective:** Enhance integration capabilities

**Tasks:**
1. **Transaction Status Queries**
   - Implement transaction status check API
   - Add manual status verification endpoints

2. **Account Balance Checks**
   - Query available balances
   - Implement balance monitoring

3. **Reversal Capabilities**
   - Handle transaction reversals
   - Implement refund workflows

**Deliverables:**
- Enhanced API capabilities
- Improved error recovery

## Technical Architecture Considerations

### Database Schema Updates
- Add M-Pesa specific fields to transactions table
- Implement callback tracking
- Add audit logging tables

### Security Measures
- HTTPS-only callbacks in production
- Request validation and sanitization
- Rate limiting on public endpoints
- Comprehensive logging without sensitive data

### Error Handling
- Graceful handling of API failures
- Retry mechanisms for transient errors
- User-friendly error messages
- Administrative alerts for critical failures

### Performance Optimization
- Asynchronous callback processing
- Database indexing for lookups
- Caching for frequently accessed data
- Queue-based processing for heavy operations

## Risk Mitigation

### Testing Strategy
- Comprehensive sandbox testing before production
- Gradual rollout with monitoring
- Fallback mechanisms for API failures

### Monitoring & Support
- Real-time callback monitoring
- Automated alerts for failures
- Support ticket escalation process
- Regular health checks

### Compliance
- Adhere to M-Pesa API terms of service
- Implement proper data protection
- Maintain audit trails for regulatory compliance

## Estimated Timeline: 2-3 weeks
- Phase 1-2: 3-5 days (Setup & Auth)
- Phase 3-4: 6-8 days (C2B & B2C core)
- Phase 5-6: 4-6 days (Testing & optional features)
- Phase 7: 2-3 days (Production deployment)

This roadmap provides a structured approach to implementing production-grade M-Pesa integration. Would you like me to proceed with implementation, or do you have any modifications to the roadmap?