Seat-Based Billing

Starter Plan: $49/month
├── Includes: 3 seats
├── Extra seats: $10/month each
└── 8 total seats = $49 + (5 × $10) = $99/month

Per User: $12/month
├── 5 users = $60/month
├── 20 users = $240/month
└── 100 users = $1,200/month

Starter: $0/month base + $15/seat
├── Lower features, higher per-seat cost

Professional: $99/month base + $10/seat
├── More features, lower per-seat cost

Enterprise: $499/month base + $7/seat
└── All features, volume discount on seats

5-Seat Pack: $50/month ($10/seat)
10-Seat Pack: $80/month ($8/seat)
25-Seat Pack: $175/month ($7/seat)

const session = await client.checkoutSessions.create({
  product_cart: [{
    product_id: 'prod_team_plan',
    quantity: 1,
    addons: [{
      addon_id: 'addon_seat',
      quantity: 10  // 10 additional seats
    }]
  }],
  customer: { email: 'admin@company.com' },
  return_url: 'https://yourapp.com/success'
});

// Add 5 more seats to existing subscription
await client.subscriptions.changePlan('sub_123', {
  product_id: 'prod_team_plan',
  quantity: 1,
  proration_billing_mode: 'prorated_immediately',
  addons: [{
    addon_id: 'addon_seat',
    quantity: 15  // New total: 15 additional seats
  }]
});

// Reduce from 15 to 8 additional seats
await client.subscriptions.changePlan('sub_123', {
  product_id: 'prod_team_plan',
  quantity: 1,
  proration_billing_mode: 'difference_immediately',
  addons: [{
    addon_id: 'addon_seat',
    quantity: 8  // Reduced to 8 additional seats
  }]
});

// Remove all additional seats, keep only base plan seats
await client.subscriptions.changePlan('sub_123', {
  product_id: 'prod_team_plan',
  quantity: 1,
  proration_billing_mode: 'difference_immediately',
  addons: []  // Removes all add-ons
});

Current: Team Plan ($99/month) + 10 extra seats × $10/seat = $199/month
Change: Remove 3 seats (10 → 7 extra seats) on day 20 of 30-day cycle
Remaining: 10 days

Credit for removed seats:
  = ($10 × 3 seats) × (10 days / 30 days)
  = $30 × 0.333
  = $10.00 credit

→ $10.00 credit added to subscription
→ Next renewal: $99 + (7 × $10) = $169.00/month
→ Credit auto-applies: $169.00 − $10.00 = $159.00 on next invoice

const preview = await client.subscriptions.previewChangePlan('sub_123', {
  product_id: 'prod_team_plan',
  quantity: 1,
  proration_billing_mode: 'prorated_immediately',
  addons: [{ addon_id: 'addon_seat', quantity: 20 }]
});

console.log('Immediate charge:', preview.immediate_charge.summary);
// Show customer: "Adding 5 seats will cost $25 today"

app.post('/webhooks/dodo', async (req, res) => {
  const event = req.body;

  switch (event.type) {
    case 'subscription.active':
      // New subscription - provision seats
      const seats = calculateTotalSeats(event.data);
      await provisionSeats(event.data.customer_id, seats);
      break;

    case 'subscription.plan_changed':
      // Seats changed - update access
      const newSeats = calculateTotalSeats(event.data);
      await updateSeatCount(event.data.subscription_id, newSeats);
      break;

    case 'subscription.cancelled':
      // Subscription cancelled - deprovision
      await deprovisionAllSeats(event.data.subscription_id);
      break;
  }

  res.json({ received: true });
});

function calculateTotalSeats(subscriptionData) {
  const baseSeats = 5;  // Included in plan
  const addonSeats = subscriptionData.addons?.reduce(
    (total, addon) => total + addon.quantity, 0
  ) || 0;
  return baseSeats + addonSeats;
}

Full Seats: $20/month - Full access to all features
View-Only Seats: $5/month - Read-only access
Guest Seats: $0/month - Limited external collaborator access

const session = await client.checkoutSessions.create({
  product_cart: [{
    product_id: 'prod_team_plan',
    quantity: 1,
    addons: [
      { addon_id: 'addon_full_seat', quantity: 10 },
      { addon_id: 'addon_viewer_seat', quantity: 25 },
      { addon_id: 'addon_guest_seat', quantity: 50 }
    ]
  }]
});

Monthly: $15/seat/month
Annual: $12/seat/month (20% savings)

async function validateSeatCount(planId: string, seatCount: number) {
  const minimums = {
    'prod_starter': 1,
    'prod_team': 5,
    'prod_enterprise': 25
  };

  if (seatCount < minimums[planId]) {
    throw new Error(`${planId} requires at least ${minimums[planId]} seats`);
  }
}