Price increase notification before new-rate renewal

Charging a consumer at a higher price than they originally authorized — with no advance notice — violates the FTC Negative Option Rule (2025) requirement that material changes to subscription terms be communicated before they take effect. California ARL and EU Consumer Rights Directive 2011/83/EU both require that price increases be disclosed with sufficient advance notice for the consumer to cancel before the new rate applies. Silent price increases processed through Stripe Subscription Schedules without customer notification are the most common way well-intentioned teams inadvertently create regulatory exposure during pricing strategy updates.

Handle customer.subscription.updated to detect price changes and trigger a 30-day-advance notification email. In app/api/webhooks/stripe/route.ts:

const priceChanged = prevSub?.items &&
  newSub.items.data[0]?.price.id !== prevSub.items.data?.[0]?.price?.id

if (priceChanged && email) {
  await sendEmail({
    to: email,
    subject: 'Important: Your subscription price is changing',
    template: 'price-change-notification',
    data: {
      oldPrice: (prevSub.items.data?.[0]?.price?.unit_amount ?? 0) / 100,
      newPrice: (newSub.items.data[0]?.price.unit_amount ?? 0) / 100,
      effectiveDate: formatDate(newSub.current_period_end),
      cancelUrl: `${process.env.NEXT_PUBLIC_APP_URL}/settings/billing`,
    },
  })
}

For planned increases, use Stripe Subscription Schedules with a future-dated phase so the notification goes out before the phase activates — not simultaneously with the price change.