Hard bounces permanently suppressed

Sending to hard-bounced addresses — permanent delivery failures where the domain does not exist or the mailbox has been closed — is one of the fastest ways to destroy sender reputation. ISPs track hard-bounce rates and use them as a primary signal for spam classification. Continued sends to bounced addresses also place you in violation of CAN-SPAM § 5, which requires honoring suppression, and trigger GDPR Art. 21 concerns when the data subject's address is clearly no longer valid. Deliverability services (Postmark, SendGrid, Mailgun) will automatically suspend accounts that exceed a ~2% hard-bounce threshold — recovery typically requires list remediation and a manual warm-up period.

Handle hard bounces with immediate, atomic suppression in the webhook handler:

// POST /api/webhooks/esp — inside bounce handler:
if (event.event === 'bounce' && event.bounce_type === 'hard') {
  const email = event.email.toLowerCase().trim()
  await db.$transaction(async (tx) => {
    await tx.suppression.upsert({
      where: { email },
      create: { email, reason: 'hard_bounce', suppressed_at: new Date(), source_event_id: event.id },
      update: { reason: 'hard_bounce', suppressed_at: new Date() }
    })
    await tx.contact.updateMany({
      where: { email },
      data: { status: 'suppressed', suppressed_at: new Date() }
    })
  })
}

Under CAN-SPAM § 5, suppression must be permanent by default. Any admin override of a hard-bounce suppression must be logged with admin ID, timestamp, and a stated reason — unsupervised re-activation is not compliant.