SaaS products need tenancy, billing, and observability from MVP—not as Series A afterthoughts.
Multi-Tenant Data Model
tenant_id on all rows; RBAC within tenant; super-admin for support impersonation with audit logs.
Subscription Billing
Stripe webhooks with idempotency keys. Handle failed payments, upgrades, and proration.
Scaling Path
Read replicas, queue workers, and feature flags before premature Kubernetes complexity.