Decoupled Next.js frontend with edge caching, Fastify TypeScript REST API gateway, shared PostgreSQL relational database with Row-Level Security (RLS), Redis distributed caching, and Docker VPS orchestration.
1. Multi-Tenant Architectural Foundations
Multi-tenancy is the architectural core of any SaaS product. Designing for multi-tenancy means deciding early between a shared database with tenant column isolation, separate schemas per tenant, or separate physical databases.
For most SaaS applications, a shared database with strict PostgreSQL Row-Level Security (RLS) and Prisma middleware provides the ideal balance between low infrastructure overhead and tenant data isolation.
- Shared database with tenant-level foreign key indexing minimizes hosting costs.
- Row-Level Security (RLS) prevents accidental cross-tenant data leaks at the database level.
- Stateless JWT tokens include verified tenant IDs to eliminate database session lookups.
2. Subscription Billing & Seat Management
Integrating Stripe or Razorpay requires robust webhook architecture. Webhooks must be idempotent: store incoming webhook event IDs in Redis or PostgreSQL to prevent processing the same billing invoice event multiple times.
Support seat-based pricing, organization workspace switching, and automated invoice PDF generation to satisfy B2B customer requirements.
- Idempotent webhook handlers prevent duplicate credit allocation.
- Seat management allows organization admins to invite team members with granular RBAC permissions.
3. Enterprise Security & Role-Based Access Control (RBAC)
Implement fine-grained permissions (Owner, Admin, Member, Viewer). Every API request must pass through an authentication plugin verifying token validity and permission scopes before executing database queries.
4. Production Cloud Deployment & Monitoring
Containerize frontend and backend services using Docker. Deploy behind Nginx reverse proxies with SSL termination, PM2 process clustering, and automated daily encrypted PostgreSQL database backups.