Multi-Tenant SaaS Dashboard with Next.js + Prisma + Stripe

The summary

Built a multi-tenant B2B SaaS from scratch — Next.js 14 App Router, Postgres + Drizzle, Clerk for auth, Stripe Billing for subscriptions, and Inngest for background jobs. Shipped to first paying customer in 9 weeks; now serves 80+ tenants.

The problem

• ▸Two non-technical founders had a validated product hypothesis but no engineering capacity. Pre-seed budget could afford one senior engineer for ~3 months.
• ▸Needed a multi-tenant architecture from day one — they expected B2B customers with workspaces, roles, and per-tenant data isolation.
• ▸Required Stripe subscriptions, organization invitations, role-based access, and a clean admin experience.

The approach

1. 1.Row-level tenant isolation enforced via Prisma extends — every query filtered by tenantId, automated in middleware so business logic never has to think about it.
2. 2.Clerk for auth (cost was worth not building auth in week 1). Their organizations + RBAC + MFA shipped on day 2.
3. 3.Stripe Billing for subscriptions. Webhook handlers idempotent via event.id dedupe. Customer Portal for self-service billing changes — massive support burden reduction from day 0.
4. 4.Postgres + Drizzle ORM for type-safe SQL. Schema designed once for multi-tenancy: Tenant → User (via Membership) → Resource (with tenantId on every row).
5. 5.Inngest for background work — onboarding emails, subscription state syncs, scheduled reports.
6. 6.Deployed on Vercel + Supabase + Resend. Total stack cost at launch: $120/mo.

Results

Tech stack

What surprised me

The single best decision was buying Clerk vs building auth. The single best architecture decision was row-level isolation enforced at the data layer — not in business logic, not in middleware, but in Prisma's extends. It made tenant scoping invisible, which means impossible to forget.