# Technical Stack - Open Source Technologies for Maternal Organization App

## Mobile Application Development

### Cross-Platform Framework
- **React Native** (Primary Choice)
  - `react-native`: Core framework
  - `react-native-cli`: Command line interface
  - `expo`: Development toolchain and libraries
  - `react-navigation`: Navigation library
  - `react-native-paper`: Material Design components
  - `react-native-elements`: UI toolkit

### Alternative Native Development
- **Flutter** (Alternative Option)
  - `flutter`: Core SDK
  - `flutter_bloc`: State management
  - `provider`: Dependency injection
  - `get_it`: Service locator
  - `dio`: HTTP client

### State Management
- **Redux Toolkit**
  - `@reduxjs/toolkit`: Modern Redux with less boilerplate
  - `react-redux`: React bindings
  - `redux-persist`: Offline data persistence
  - `redux-offline`: Offline-first functionality
  - `redux-saga`: Side effects management

### Local Database & Storage
- **SQLite** (Primary local database)
  - `react-native-sqlite-storage`: SQLite for React Native
  - `typeorm`: Object-relational mapping
  - `realm`: Alternative mobile database
  
- **Async Storage**
  - `@react-native-async-storage/async-storage`: Key-value storage
  - `react-native-mmkv`: Fast key-value storage alternative

## Backend Infrastructure

### Core Backend Framework
- **Node.js** with **NestJS**
  - `@nestjs/core`: Enterprise-grade Node.js framework
  - `@nestjs/common`: Common utilities
  - `@nestjs/platform-express`: Express adapter
  - `@nestjs/microservices`: Microservices support
  - `@nestjs/websockets`: WebSocket support
  - `@nestjs/graphql`: GraphQL integration

### API Development
- **GraphQL**
  - `apollo-server-express`: GraphQL server
  - `type-graphql`: TypeScript GraphQL framework
  - `graphql-subscriptions`: Real-time subscriptions
  - `graphql-upload`: File upload handling
  
- **REST API**
  - `express`: Web framework
  - `fastify`: Alternative high-performance framework
  - `cors`: Cross-origin resource sharing
  - `helmet`: Security headers
  - `compression`: Response compression

### Database Systems
- **PostgreSQL** (Primary database)
  - `pg`: PostgreSQL client
  - `knex`: SQL query builder
  - `prisma`: Modern ORM
  - `typeorm`: Alternative ORM
  
- **MongoDB** (Document storage)
  - `mongoose`: MongoDB object modeling
  - `mongodb`: Native driver

### Caching & Performance
- **Redis**
  - `redis`: Redis client
  - `ioredis`: Advanced Redis client
  - `bull`: Queue management
  - `node-cache`: In-memory caching
  
- **Elasticsearch** (Search & analytics)
  - `@elastic/elasticsearch`: Official client
  - `searchkit`: Search UI components

## AI & Machine Learning

### LLM Integration (Proprietary APIs)
- **OpenAI API** / **Anthropic Claude API** / **Google Gemini API**
- **LangChain** (Framework)
  - `langchain`: Core library
  - `@langchain/community`: Community integrations
  - `@langchain/openai`: OpenAI integration

### Open Source ML/AI
- **TensorFlow.js**
  - `@tensorflow/tfjs`: Core library
  - `@tensorflow/tfjs-node`: Node.js bindings
  - `@tensorflow/tfjs-react-native`: React Native support
  
- **ONNX Runtime**
  - `onnxruntime-node`: Node.js inference
  - `onnxruntime-react-native`: Mobile inference

### Natural Language Processing
- **Natural**
  - `natural`: General NLP tasks
  - `compromise`: Natural language understanding
  - `sentiment`: Sentiment analysis
  - `franc`: Language detection

### Pattern Recognition & Analytics
- **Time Series Analysis**
  - `timeseries-analysis`: Time series forecasting
  - `simple-statistics`: Statistical functions
  - `regression`: Regression analysis
  
- **Data Processing**
  - `pandas-js`: Data manipulation
  - `dataframe-js`: DataFrame operations
  - `ml-js`: Machine learning algorithms

## Real-Time Communication

### WebSocket & Real-Time Sync
- **Socket.io**
  - `socket.io`: Server implementation
  - `socket.io-client`: Client library
  - `socket.io-redis`: Redis adapter for scaling

### Push Notifications
- **Firebase Cloud Messaging** (Free tier available)
  - `firebase-admin`: Server SDK
  - `react-native-firebase`: React Native integration
  
- **Alternative: Expo Push Notifications**
  - `expo-notifications`: Notification handling
  - `expo-server-sdk`: Server implementation

## Voice & Audio Processing

### Voice Input & Recognition
- **Whisper** (OpenAI's open source)
  - `whisper`: Speech recognition
  - `react-native-voice`: Voice recognition wrapper
  
- **Web Speech API**
  - `react-speech-kit`: React speech components
  - `speech-to-text`: Browser-based recognition

### Audio Processing
- **FFmpeg**
  - `fluent-ffmpeg`: Node.js wrapper
  - `react-native-ffmpeg`: Mobile integration
  
- **Web Audio API**
  - `tone.js`: Audio synthesis and effects
  - `wavesurfer.js`: Audio visualization

## Security & Privacy

### Authentication & Authorization
- **Supabase** (Open source Firebase alternative)
  - `@supabase/supabase-js`: Client library
  - `@supabase/auth-helpers`: Authentication utilities
  
- **Passport.js**
  - `passport`: Authentication middleware
  - `passport-jwt`: JWT strategy
  - `passport-local`: Local strategy

### Encryption & Security
- **Cryptography**
  - `bcrypt`: Password hashing
  - `jsonwebtoken`: JWT tokens
  - `crypto-js`: Encryption utilities
  - `node-forge`: Cryptography toolkit
  
- **Security Middleware**
  - `helmet`: Security headers
  - `express-rate-limit`: Rate limiting
  - `express-validator`: Input validation
  - `hpp`: HTTP parameter pollution prevention

### COPPA/GDPR Compliance
- **Age Verification**
  - `age-calculator`: Age calculation utilities
  - Custom implementation required
  
- **Data Privacy**
  - `anonymize`: Data anonymization
  - `gdpr-guard`: GDPR compliance helpers

## File & Media Management

### Image Processing
- **Sharp**
  - `sharp`: High-performance image processing
  - `react-native-image-resizer`: Mobile image resizing
  - `react-native-image-picker`: Image selection

### File Storage
- **MinIO** (Self-hosted S3-compatible)
  - `minio`: Object storage server
  - `multer`: File upload middleware
  - `multer-s3`: S3 storage engine

### Document Processing
- **PDF Generation**
  - `pdfkit`: PDF generation
  - `puppeteer`: HTML to PDF conversion
  - `react-native-pdf`: PDF viewing

## Calendar & Scheduling

### Calendar Integration
- **Calendar Libraries**
  - `node-ical`: iCal parsing
  - `ical-generator`: iCal generation
  - `react-native-calendars`: Calendar components
  - `react-big-calendar`: Web calendar component

### Scheduling
- **Cron Jobs**
  - `node-cron`: Task scheduling
  - `agenda`: Job scheduling
  - `bull`: Queue-based job processing

## Integration Libraries

### External Service Integrations
- **Google APIs**
  - `googleapis`: Google services client
  - `@react-native-google-signin/google-signin`: Google sign-in
  
- **Microsoft Graph**
  - `@microsoft/microsoft-graph-client`: Graph API client
  
- **School Platforms**
  - Custom API integrations required
  - `axios`: HTTP client for API calls

### Smart Home Integration
- **Home Assistant**
  - `home-assistant-js-websocket`: WebSocket client
  
- **Voice Assistants**
  - `ask-sdk`: Alexa Skills Kit
  - `actions-on-google`: Google Assistant

## Data Visualization & Analytics

### Charting Libraries
- **D3.js Ecosystem**
  - `d3`: Core visualization library
  - `react-native-svg`: SVG support for React Native
  - `victory-native`: React Native charts
  
- **Chart.js**
  - `chart.js`: Charting library
  - `react-chartjs-2`: React wrapper
  - `react-native-chart-kit`: React Native charts

### Analytics
- **Matomo** (Open source analytics)
  - `matomo-tracker`: Analytics tracking
  
- **PostHog** (Open source product analytics)
  - `posthog-js`: JavaScript client
  - `posthog-react-native`: React Native client

## Development Tools

### Testing Frameworks
- **Unit Testing**
  - `jest`: Testing framework
  - `@testing-library/react-native`: React Native testing
  - `enzyme`: Component testing
  
- **E2E Testing**
  - `detox`: React Native E2E testing
  - `appium`: Cross-platform mobile testing
  - `cypress`: Web testing

### Code Quality
- **Linting & Formatting**
  - `eslint`: JavaScript linter
  - `prettier`: Code formatter
  - `husky`: Git hooks
  - `lint-staged`: Pre-commit linting

### Development Environment
- **Build Tools**
  - `webpack`: Module bundler
  - `babel`: JavaScript compiler
  - `metro`: React Native bundler
  
- **Development Servers**
  - `nodemon`: Node.js auto-restart
  - `concurrently`: Run multiple commands
  - `dotenv`: Environment variables

## DevOps & Infrastructure

### Container Orchestration
- **Docker**
  - `docker`: Containerization
  - `docker-compose`: Multi-container apps
  
- **Kubernetes** (for scaling)
  - `kubernetes`: Container orchestration
  - `helm`: Kubernetes package manager

### CI/CD
- **GitHub Actions** / **GitLab CI** / **Jenkins**
  - `semantic-release`: Automated versioning
  - `standard-version`: Changelog generation

### Monitoring & Logging
- **Sentry** (Open source error tracking)
  - `@sentry/node`: Node.js SDK
  - `@sentry/react-native`: React Native SDK
  
- **Winston** (Logging)
  - `winston`: Logging library
  - `morgan`: HTTP request logger

### Message Queue
- **RabbitMQ**
  - `amqplib`: RabbitMQ client
  
- **Apache Kafka** (for high scale)
  - `kafkajs`: Kafka client

## Additional Utilities

### Date & Time
- `dayjs`: Lightweight date library
- `date-fns`: Date utility library
- `moment-timezone`: Timezone handling
- `react-native-date-picker`: Date picker component

### Forms & Validation
- `react-hook-form`: Form management
- `yup`: Schema validation
- `joi`: Object schema validation
- `react-native-masked-text`: Input masking

### Localization
- `i18next`: Internationalization framework
- `react-i18next`: React integration
- `react-native-localize`: Device locale detection

### Utilities
- `lodash`: Utility functions
- `uuid`: UUID generation
- `validator`: String validators
- `numeral`: Number formatting

## Infrastructure Services (Self-Hosted Options)

### Backend as a Service
- **Supabase** (Complete backend solution)
- **Appwrite** (Alternative BaaS)
- **Parse Server** (Mobile backend)

### Search Infrastructure
- **Meilisearch** (Fast search engine)
- **Typesense** (Typo-tolerant search)

### Email Service
- **Nodemailer** with SMTP
- **SendGrid** (Free tier available)
- **Postal** (Self-hosted)

## Performance Optimization

### Mobile Performance
- `react-native-fast-image`: Optimized image loading
- `react-native-super-grid`: Efficient grid rendering
- `recyclerlistview`: High-performance lists
- `react-native-reanimated`: Smooth animations

### Backend Performance
- `cluster`: Node.js clustering
- `pm2`: Process management
- `compression`: Response compression
- `memory-cache`: In-memory caching

## Accessibility Tools
- `react-native-accessibility`: Accessibility utilities
- `react-native-tts`: Text-to-speech
- `react-native-screen-reader`: Screen reader detection

## Development Recommendations

### Minimum Viable Stack
1. **Frontend**: React Native + Expo
2. **Backend**: NestJS + PostgreSQL
3. **Real-time**: Socket.io
4. **AI**: OpenAI/Claude API + LangChain
5. **Auth**: Supabase Auth
6. **Storage**: MinIO/Supabase Storage
7. **Cache**: Redis
8. **Search**: Meilisearch

### Scalability Considerations
- Start with monolithic backend, prepare for microservices
- Use message queues early for async operations
- Implement caching strategy from day one
- Design for offline-first mobile experience
- Plan for horizontal scaling with Kubernetes

### Security Priorities
- Implement end-to-end encryption for sensitive data
- Use JWT with refresh tokens
- Apply rate limiting on all endpoints
- Regular security audits with OWASP tools
- COPPA/GDPR compliance from the start