# Architecture

Technical architecture and design principles for Mosaic Stack.

## Chapters

1. **Overview** — System design and component architecture
2. **Authentication** — BetterAuth integration and OIDC flow
3. **Design Principles** — PDA-friendly patterns and UX guidelines

## Architecture Principles

- **Type Safety First:** Shared types prevent frontend/backend drift
- **Multi-Tenant Ready:** Row-level security with workspace isolation
- **PDA-Friendly:** Calm, stress-free language and visual design
- **Modular:** Plugin architecture for extensibility

## Technology Decisions

Key architectural choices and their rationale:

- **BetterAuth** over Passport.js for modern authentication
- **Prisma ORM** for type-safe database access
- **Monorepo** with pnpm workspaces for code sharing
- **PostgreSQL + pgvector** for AI-ready data storage

## Next Steps

- Review **API** for implementation details
- Check **Development** for workflow standards