Saas Scaffolder

Generated File Tree

my-saas/
├── app/
│   ├── (auth)/
│   │   ├── login/page.tsx
│   │   ├── register/page.tsx
│   │   ├── forgot-password/page.tsx
│   │   └── layout.tsx
│   ├── (dashboard)/
│   │   ├── dashboard/page.tsx
│   │   ├── settings/
│   │   │   ├── page.tsx              # Profile settings
│   │   │   ├── billing/page.tsx      # Subscription management
│   │   │   └── team/page.tsx         # Team/workspace settings
│   │   └── layout.tsx                # Dashboard shell (sidebar + header)
│   ├── (marketing)/
│   │   ├── page.tsx                  # Landing page
│   │   ├── pricing/page.tsx          # Pricing tiers
│   │   └── layout.tsx
│   ├── api/
│   │   ├── auth/[...nextauth]/route.ts
│   │   ├── webhooks/stripe/route.ts
│   │   ├── billing/
│   │   │   ├── checkout/route.ts
│   │   │   └── portal/route.ts
│   │   └── health/route.ts
│   ├── layout.tsx                    # Root layout
│   └── not-found.tsx
├── components/
│   ├── ui/                           # shadcn/ui components
│   ├── auth/
│   │   ├── login-form.tsx
│   │   └── register-form.tsx
│   ├── dashboard/
│   │   ├── sidebar.tsx
│   │   ├── header.tsx
│   │   └── stats-card.tsx
│   ├── marketing/
│   │   ├── hero.tsx
│   │   ├── features.tsx
│   │   ├── pricing-card.tsx
│   │   └── footer.tsx
│   └── billing/
│       ├── plan-card.tsx
│       └── usage-meter.tsx
├── lib/
│   ├── auth.ts                       # Auth configuration
│   ├── db.ts                         # Database client singleton
│   ├── stripe.ts                     # Stripe client
│   ├── validations.ts                # Zod schemas
│   └── utils.ts                      # Shared utilities
├── db/
│   ├── schema.ts                     # Drizzle schema
│   ├── migrations/                   # Generated migrations
│   └── seed.ts                       # Development seed data
├── hooks/
│   ├── use-subscription.ts
│   └── use-current-user.ts
├── types/
│   └── index.ts                      # Shared TypeScript types
├── middleware.ts                      # Auth + rate limiting
├── .env.example
├── drizzle.config.ts
├── tailwind.config.ts
└── next.config.ts

Database Schema (Multi-Tenant)

// db/schema.ts
import { pgTable, text, timestamp, integer, boolean, uniqueIndex, index } from 'drizzle-orm/pg-core'
import { createId } from '@paralleldrive/cuid2'

// ──── WORKSPACES (Tenancy boundary) ────
export const workspaces = pgTable('workspaces', {
  id: text('id').primaryKey().$defaultFn(createId),
  name: text('name').notNull(),
  slug: text('slug').notNull(),
  plan: text('plan').notNull().default('free'),  // free | pro | enterprise
  stripeCustomerId: text('stripe_customer_id').unique(),
  stripeSubscriptionId: text('stripe_subscription_id'),
  stripePriceId: text('stripe_price_id'),
  stripeCurrentPeriodEnd: timestamp('stripe_current_period_end'),
  createdAt: timestamp('created_at', { withTimezone: true }).defaultNow().notNull(),
  updatedAt: timestamp('updated_at', { withTimezone: true }).defaultNow().notNull(),
}, (t) => [
  uniqueIndex('workspaces_slug_idx').on(t.slug),
])

// ──── USERS ────
export const users = pgTable('users', {
  id: text('id').primaryKey().$defaultFn(createId),
  email: text('email').notNull().unique(),
  name: text('name'),
  avatarUrl: text('avatar_url'),
  emailVerified: timestamp('email_verified', { withTimezone: true }),
  createdAt: timestamp('created_at', { withTimezone: true }).defaultNow().notNull(),
})

// ──── WORKSPACE MEMBERS ────
export const workspaceMembers = pgTable('workspace_members', {
  id: text('id').primaryKey().$defaultFn(createId),
  workspaceId: text('workspace_id').notNull().references(() => workspaces.id, { onDelete: 'cascade' }),
  userId: text('user_id').notNull().references(() => users.id, { onDelete: 'cascade' }),
  role: text('role').notNull().default('member'), // owner | admin | member
  joinedAt: timestamp('joined_at', { withTimezone: true }).defaultNow().notNull(),
}, (t) => [
  uniqueIndex('workspace_members_unique').on(t.workspaceId, t.userId),
  index('workspace_members_workspace_idx').on(t.workspaceId),
])

// ──── ACCOUNTS (OAuth) ────
export const accounts = pgTable('accounts', {
  userId: text('user_id').notNull().references(() => users.id, { onDelete: 'cascade' }),
  type: text('type').notNull(),
  provider: text('provider').notNull(),
  providerAccountId: text('provider_account_id').notNull(),
  refreshToken: text('refresh_token'),
  accessToken: text('access_token'),
  expiresAt: integer('expires_at'),
})

// ──── SESSIONS ────
export const sessions = pgTable('sessions', {
  sessionToken: text('session_token').primaryKey(),
  userId: text('user_id').notNull().references(() => users.id, { onDelete: 'cascade' }),
  expires: timestamp('expires', { withTimezone: true }).notNull(),
})

Authentication Configuration

// lib/auth.ts
import { DrizzleAdapter } from '@auth/drizzle-adapter'
import NextAuth from 'next-auth'
import Google from 'next-auth/providers/google'
import GitHub from 'next-auth/providers/github'
import Resend from 'next-auth/providers/resend'
import { db } from './db'

export const { handlers, auth, signIn, signOut } = NextAuth({
  adapter: DrizzleAdapter(db),
  providers: [
    Google({
      clientId: process.env.GOOGLE_CLIENT_ID!,
      clientSecret: process.env.GOOGLE_CLIENT_SECRET!,
    }),
    GitHub({
      clientId: process.env.GITHUB_CLIENT_ID!,
      clientSecret: process.env.GITHUB_CLIENT_SECRET!,
    }),
    Resend({
      from: '[email protected]',
    }),
  ],
  callbacks: {
    session: async ({ session, user }) => ({
      ...session,
      user: {
        ...session.user,
        id: user.id,
      },
    }),
  },
  pages: {
    signIn: '/login',
    error: '/login',
  },
})

Stripe Billing Integration

Checkout Session

// app/api/billing/checkout/route.ts
import { NextResponse } from 'next/server'
import { auth } from '@/lib/auth'
import { stripe } from '@/lib/stripe'
import { db } from '@/lib/db'
import { workspaces } from '@/db/schema'
import { eq } from 'drizzle-orm'

export async function POST(req: Request) {
  const session = await auth()
  if (!session?.user) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
  }

  const { priceId, workspaceId } = await req.json()

  // Get or create Stripe customer
  const [workspace] = await db.select().from(workspaces).where(eq(workspaces.id, workspaceId))
  if (!workspace) {
    return NextResponse.json({ error: 'Workspace not found' }, { status: 404 })
  }

  let customerId = workspace.stripeCustomerId
  if (!customerId) {
    const customer = await stripe.customers.create({
      email: session.user.email!,
      metadata: { workspaceId },
    })
    customerId = customer.id
    await db.update(workspaces)
      .set({ stripeCustomerId: customerId })
      .where(eq(workspaces.id, workspaceId))
  }

  const checkoutSession = await stripe.checkout.sessions.create({
    customer: customerId,
    mode: 'subscription',
    payment_method_types: ['card'],
    line_items: [{ price: priceId, quantity: 1 }],
    success_url: `${process.env.NEXT_PUBLIC_APP_URL}/settings/billing?success=true`,
    cancel_url: `${process.env.NEXT_PUBLIC_APP_URL}/pricing`,
    subscription_data: { trial_period_days: 14 },
    metadata: { workspaceId },
  })

  return NextResponse.json({ url: checkoutSession.url })
}

Webhook Handler

// app/api/webhooks/stripe/route.ts
import { headers } from 'next/headers'
import { stripe } from '@/lib/stripe'
import { db } from '@/lib/db'
import { workspaces } from '@/db/schema'
import { eq } from 'drizzle-orm'

export async function POST(req: Request) {
  const body = await req.text()
  const signature = (await headers()).get('Stripe-Signature')!

  let event
  try {
    event = stripe.webhooks.constructEvent(body, signature, process.env.STRIPE_WEBHOOK_SECRET!)
  } catch (err) {
    return new Response(`Webhook Error: ${err.message}`, { status: 400 })
  }

  switch (event.type) {
    case 'checkout.session.completed': {
      const session = event.data.object
      const subscription = await stripe.subscriptions.retrieve(session.subscription as string)
      await db.update(workspaces).set({
        stripeSubscriptionId: subscription.id,
        stripePriceId: subscription.items.data[0].price.id,
        stripeCurrentPeriodEnd: new Date(subscription.current_period_end * 1000),
      }).where(eq(workspaces.stripeCustomerId, session.customer as string))
      break
    }

    case 'invoice.payment_succeeded': {
      const invoice = event.data.object
      const subscription = await stripe.subscriptions.retrieve(invoice.subscription as string)
      await db.update(workspaces).set({
        stripeCurrentPeriodEnd: new Date(subscription.current_period_end * 1000),
      }).where(eq(workspaces.stripeCustomerId, invoice.customer as string))
      break
    }

    case 'customer.subscription.deleted': {
      const subscription = event.data.object
      await db.update(workspaces).set({
        plan: 'free',
        stripeSubscriptionId: null,
        stripePriceId: null,
        stripeCurrentPeriodEnd: null,
      }).where(eq(workspaces.stripeCustomerId, subscription.customer as string))
      break
    }
  }

  return new Response('OK', { status: 200 })
}

Middleware (Auth + Rate Limiting)

// middleware.ts
import { auth } from '@/lib/auth'
import { NextResponse } from 'next/server'

export default auth((req) => {
  const { pathname } = req.nextUrl
  const isAuthenticated = !!req.auth

  // Protected routes
  if (pathname.startsWith('/dashboard') || pathname.startsWith('/settings')) {
    if (!isAuthenticated) {
      return NextResponse.redirect(new URL('/login', req.url))
    }
  }

  // Redirect logged-in users away from auth pages
  if ((pathname === '/login' || pathname === '/register') && isAuthenticated) {
    return NextResponse.redirect(new URL('/dashboard', req.url))
  }

  return NextResponse.next()
})

export const config = {
  matcher: ['/dashboard/:path*', '/settings/:path*', '/login', '/register'],
}

Environment Variables

# .env.example

# ─── App ───
NEXT_PUBLIC_APP_URL=http://localhost:3000
NEXTAUTH_SECRET=           # openssl rand -base64 32
NEXTAUTH_URL=http://localhost:3000

# ─── Database ───
DATABASE_URL=              # postgresql://user:pass@host/db?sslmode=require

# ─── OAuth Providers ───
GOOGLE_CLIENT_ID=
GOOGLE_CLIENT_SECRET=
GITHUB_CLIENT_ID=
GITHUB_CLIENT_SECRET=

# ─── Stripe ───
STRIPE_SECRET_KEY=sk_test_...
STRIPE_WEBHOOK_SECRET=whsec_...
NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY=pk_test_...
STRIPE_PRO_MONTHLY_PRICE_ID=price_...
STRIPE_PRO_YEARLY_PRICE_ID=price_...

# ─── Email ───
RESEND_API_KEY=re_...

# ─── Monitoring (optional) ───
SENTRY_DSN=

Scaffolding Phases

Execute these phases in order. Validate at the end of each phase.

Phase 1: Foundation

1. Initialize Next.js with TypeScript and App Router
2. Configure Tailwind CSS with custom theme
3. Install and configure shadcn/ui
4. Set up ESLint and Prettier
5. Create .env.example

Validate: pnpm build completes without errors.

Phase 2: Database

6. Install and configure Drizzle ORM
7. Write schema (users, accounts, sessions, workspaces, members)
8. Generate and apply initial migration
9. Export DB client singleton from lib/db.ts
10. Create seed script with test data

Validate: pnpm db:push succeeds and pnpm db:seed creates test data.

Phase 3: Authentication

11. Install and configure NextAuth v5 with Drizzle adapter
12. Set up OAuth providers (Google, GitHub)
13. Create auth API route
14. Implement middleware for route protection
15. Build login and register pages

Validate: OAuth login works, session persists, protected routes redirect.

Phase 4: Billing

16. Initialize Stripe client
17. Create checkout session API route
18. Create customer portal API route
19. Implement webhook handler with signature verification
20. Build pricing page and billing settings page

Validate: Complete a test checkout with card 4242 4242 4242 4242. Verify subscription data written to DB. Replay webhook event and confirm idempotency.

Phase 5: UI and Polish

21. Build landing page (hero, features, pricing, footer)
22. Build dashboard layout (sidebar, header, stats)
23. Build settings pages (profile, billing, team)
24. Add loading states, error boundaries, and not-found pages
25. Configure deployment (Vercel/Railway)

Validate: pnpm build succeeds. All routes render correctly. No hydration errors.

Multi-Tenancy Patterns

Workspace-Scoped Queries

// Every data query must be scoped to the current workspace
export async function getProjects(workspaceId: string) {
  return db.query.projects.findMany({
    where: eq(projects.workspaceId, workspaceId),
    orderBy: [desc(projects.updatedAt)],
  })
}

// Middleware: resolve workspace from URL or session
export function getCurrentWorkspace(req: Request) {
  // Option A: workspace slug in URL (/workspace/acme/dashboard)
  // Option B: workspace ID in session/cookie
  // Option C: header (X-Workspace-Id) for API calls
}

Plan-Based Feature Gating

export function canAccessFeature(workspace: Workspace, feature: string): boolean {
  const PLAN_FEATURES: Record<string, string[]> = {
    free: ['basic_dashboard', 'up_to_3_members'],
    pro: ['advanced_analytics', 'up_to_20_members', 'custom_domain', 'api_access'],
    enterprise: ['sso', 'unlimited_members', 'audit_log', 'sla'],
  }

  const isActive = workspace.stripeCurrentPeriodEnd
    ? workspace.stripeCurrentPeriodEnd > new Date()
    : workspace.plan === 'free'

  if (!isActive) return PLAN_FEATURES.free.includes(feature)
  return PLAN_FEATURES[workspace.plan]?.includes(feature) ?? false
}

Common Pitfalls

• Missing NEXTAUTH_SECRET in production — causes session errors; generate with openssl rand -base64 32
• Webhook signature verification skipped — always verify Stripe webhook signatures; test with stripe listen
• workspace:* in session but not refreshed — stale subscription data; recheck on billing pages
• Edge Runtime conflicts with Drizzle — Drizzle needs Node.js runtime; set export const runtime = 'nodejs' on API routes
• No idempotent webhook handling — Stripe may send duplicate events; use event.id for deduplication
• Hardcoded Stripe price IDs — store in env vars, not in code; prices change between test and live mode

Best Practices

1. Stripe singleton — create the client once in lib/stripe.ts, import everywhere
2. Server actions for form mutations — use Next.js Server Actions instead of API routes for forms
3. Idempotent webhook handlers — check if the event was already processed before writing to DB
4. Suspense boundaries for async data — wrap dashboard data in <Suspense> with loading skeletons
5. Feature gating at the server level — check stripeCurrentPeriodEnd on the server, not the client
6. Rate limiting on auth routes — prevent brute force with Upstash Redis + @upstash/ratelimit
7. Workspace context in every query — never query without scoping to the current workspace
8. Test with Stripe CLI — stripe listen --forward-to localhost:3000/api/webhooks/stripe for local development

Troubleshooting

Success Criteria

• Scaffolded project passes pnpm build with zero errors and zero TypeScript warnings on first run
• End-to-end authentication flow (register, login, logout, password reset) completes in under 60 seconds of manual testing
• Stripe checkout creates a subscription and webhook handler updates the database within 5 seconds of payment completion
• Multi-tenant data isolation verified: queries scoped to Workspace A return zero rows belonging to Workspace B
• Lighthouse performance score on the landing page is 90+ on mobile with no accessibility violations at the AA level
• Time from git clone to running local dev server with seeded data is under 10 minutes following the generated README
• All environment variables are documented in .env.example with descriptions, and the app fails fast with clear error messages when required variables are missing

Scope & Limitations

This skill covers:

• Full-stack SaaS scaffolding with Next.js App Router, TypeScript, Tailwind, and shadcn/ui
• Authentication setup with NextAuth v5, Clerk, or Supabase Auth including OAuth and magic link providers
• Stripe and Lemon Squeezy billing integration with checkout, webhooks, and customer portal
• Multi-tenancy patterns (workspace/organization) with role-based access and plan-based feature gating

This skill does NOT cover:

• Ongoing Stripe billing logic beyond initial integration (metered billing, usage-based pricing, invoicing customization) — see stripe-integration-expert
• Database schema design decisions beyond the core tenancy model (complex relational modeling, indexing strategies) — see database-schema-designer
• CI/CD pipeline configuration, deployment automation, or infrastructure provisioning — see ci-cd-pipeline-builder
• API design standards, versioning, or OpenAPI specification generation — see api-design-reviewer

Integration Points