SaaS MVPs fail when billing, auth, and analytics are treated as “phase two.” We scaffold NestJS APIs with tenant isolation at the database layer, Stripe webhooks with idempotency from the first subscription plan, and PostHog events for activation funnels before marketing spends a dollar.
Multi-tenancy is a product decision, not just a schema prefix. Row-level security, feature flags per plan, and admin impersonation with audit logs are defaults in our SaaS templates–built on PostgreSQL and Redis for session and rate-limit state.
Next.js handles the marketing site and authenticated app shell with shared design tokens. Role-based feature gating mirrors API permissions so the UI never promises capabilities the backend will reject.
Usage metering and quota enforcement round out the stack: track what customers consume, surface it in admin dashboards, and connect overage logic to Stripe before finance has to reconcile spreadsheets manually.
