# Technology Stack

## Overview
This document defines the technology choices, framework decisions, and technical constraints for this project. All development must align with these technical decisions.

## Core Technologies

### Programming Languages
**Primary Language**: [e.g., TypeScript, Python, Java]
- **Version**: [e.g., TypeScript 5.x, Python 3.11+]
- **Justification**: [Why this language was chosen]

**Additional Languages**: [e.g., JavaScript, SQL]
- **Use Cases**: [When to use each language]

Example:
```
- TypeScript: Primary language for all application code
- JavaScript: Legacy code only (being migrated)
- SQL: Database queries and migrations
- Bash: Build scripts and automation
```

## Framework & Libraries

### Frontend (if applicable)
**Primary Framework**: [e.g., React, Vue.js, Angular, Svelte]
- **Version**: [e.g., React 18.x]
- **UI Library**: [e.g., Material-UI, Tailwind CSS, Chakra UI]
- **State Management**: [e.g., Redux, Zustand, Jotai, Context API]
- **Routing**: [e.g., React Router, Next.js Router]

Example:
```
- React 18.3.1 with TypeScript
- Next.js 14 (App Router)
- Tailwind CSS for styling
- Zustand for state management
- React Query for server state
```

### Backend (if applicable)
**Primary Framework**: [e.g., Express, NestJS, FastAPI, Django, Spring Boot]
- **Version**: [e.g., NestJS 10.x]
- **ORM/Database Client**: [e.g., Prisma, TypeORM, SQLAlchemy]
- **API Style**: [REST, GraphQL, gRPC]

Example:
```
- NestJS 10.x with TypeScript
- Prisma ORM for database access
- REST API with OpenAPI documentation
- Bull for background jobs
```

### Database
**Primary Database**: [e.g., PostgreSQL, MySQL, MongoDB]
- **Version**: [e.g., PostgreSQL 15+]
- **Justification**: [Why this database]
- **Cache Layer**: [e.g., Redis, Memcached]

Example:
```
- PostgreSQL 15.x (primary data store)
- Redis 7.x (caching and session storage)
- Elasticsearch 8.x (full-text search)
```

## Development Tools

### Package Management
- **Package Manager**: [npm, yarn, pnpm, pip, maven]
- **Version**: [e.g., npm 10.x, pnpm 8.x]
- **Lock File**: [package-lock.json, pnpm-lock.yaml, requirements.txt]

### Build Tools
- **Bundler**: [e.g., Webpack, Vite, Rollup, esbuild]
- **Transpiler**: [e.g., Babel, tsc, swc]
- **Task Runner**: [e.g., npm scripts, Make, Gradle]

Example:
```
- pnpm for package management
- Vite for development and bundling
- TypeScript compiler (tsc) for type checking
- Turbo for monorepo builds
```

### Testing
**Unit Testing**: [e.g., Jest, Vitest, Pytest, JUnit]
**Integration Testing**: [e.g., Supertest, TestContainers]
**E2E Testing**: [e.g., Playwright, Cypress, Selenium]
**Test Coverage Target**: [e.g., 80% minimum]

Example:
```
- Vitest for unit tests
- React Testing Library for component tests
- Playwright for E2E tests
- 80% code coverage target
```

### Code Quality
- **Linter**: [e.g., ESLint, Pylint, Checkstyle]
- **Formatter**: [e.g., Prettier, Black, Google Java Format]
- **Type Checker**: [e.g., TypeScript, mypy, Flow]
- **Pre-commit Hooks**: [e.g., Husky, pre-commit]

Example:
```
- ESLint with TypeScript plugin
- Prettier for code formatting
- Husky for pre-commit hooks
- lint-staged for staged files only
```

## Deployment & Infrastructure

### Hosting
**Platform**: [e.g., Vercel, AWS, Google Cloud, Azure, Heroku]
- **Environment**: [Serverless, Containers, VMs]
- **Region**: [e.g., us-east-1, eu-west-1]

Example:
```
- Vercel for frontend (Next.js)
- AWS ECS for backend services
- CloudFront for CDN
- Route53 for DNS
```

### CI/CD
**Pipeline**: [e.g., GitHub Actions, GitLab CI, Jenkins]
- **Stages**: [Build, Test, Deploy]
- **Deployment Strategy**: [e.g., Blue-Green, Canary, Rolling]

Example:
```
- GitHub Actions for CI/CD
- Automatic preview deployments for PRs
- Production deployment on main branch merge
- Rollback capability via Git tags
```

### Monitoring & Logging
- **Application Monitoring**: [e.g., Sentry, DataDog, New Relic]
- **Logging**: [e.g., CloudWatch, ELK Stack, Splunk]
- **Metrics**: [e.g., Prometheus, Grafana]

## Technical Constraints

### Performance Requirements
- **Page Load Time**: [e.g., < 3 seconds]
- **API Response Time**: [e.g., < 200ms for 95th percentile]
- **Concurrent Users**: [e.g., Support 10,000 concurrent users]

### Browser/Platform Support
- **Browsers**: [e.g., Chrome 90+, Firefox 88+, Safari 14+, Edge 90+]
- **Mobile**: [iOS 14+, Android 10+]
- **Node Version**: [e.g., Node.js 18.x LTS or higher]

### Security Requirements
- **Authentication**: [e.g., OAuth 2.0, JWT]
- **Authorization**: [e.g., RBAC, ABAC]
- **Data Encryption**: [e.g., TLS 1.3, AES-256]
- **Secret Management**: [e.g., AWS Secrets Manager, Vault]

Example:
```
- OAuth 2.0 with JWT tokens
- RBAC for authorization
- TLS 1.3 for all communications
- AWS Secrets Manager for secrets
- bcrypt for password hashing
```

## Third-Party Services

### Required Services
- **Service Name**: [Purpose and version/plan]

Example:
```
- Stripe: Payment processing (Standard plan)
- SendGrid: Transactional emails
- AWS S3: File storage
- Auth0: User authentication (alternative to custom auth)
```

## Technology Decisions & ADRs

### Architecture Decision Records
Document significant technical decisions:
1. **Decision**: [Brief description]
   - **Reason**: [Why this choice]
   - **Alternatives Considered**: [Other options]
   - **Date**: [When decided]

Example:
```
1. Decision: Use Next.js App Router instead of Pages Router
   - Reason: Better performance with React Server Components
   - Alternatives: Pages Router, Remix, Pure React SPA
   - Date: 2024-01-15

2. Decision: PostgreSQL instead of MongoDB
   - Reason: Relational data model fits our domain
   - Alternatives: MongoDB, MySQL
   - Date: 2024-01-10
```

## Deprecated Technologies

List technologies being phased out:
- **Technology**: [Reason for deprecation]
- **Migration Plan**: [How to migrate]
- **Deadline**: [When to complete migration]

Example:
```
- Redux: Moving to Zustand for simpler state management
  - Migration: Convert Redux stores to Zustand stores
  - Deadline: Q2 2024

- Webpack: Moving to Vite for faster builds
  - Migration: Update build configuration
  - Deadline: Q1 2024
```

## Development Environment Setup

### Prerequisites
```bash
# Required installations
Node.js 18+ (LTS)
pnpm 8+
PostgreSQL 15+
Redis 7+
Docker (optional, for local development)
```

### Quick Start
```bash
# Install dependencies
pnpm install

# Setup environment
cp .env.example .env

# Run database migrations
pnpm db:migrate

# Start development server
pnpm dev
```

---

**Note**: This document should be updated when technology choices change. Document decisions and their rationale to maintain institutional knowledge.

**Last Updated**: [Auto-generated by Steering Agent]