How do I handle email bounces and complaints automatically?

To handle email bounces and complaints automatically, set up a feedback loop that listens for delivery events from your email provider and updates your recipient list in real time.

1) Use a provider that sends event notifications

Most email services can push events like:

• Delivered
• Bounce (hard/soft)
• Complaint / abuse report
• Unsubscribe

Examples: Amazon SES, SendGrid, Mailgun, Postmark, SparkPost.

2) Subscribe to webhooks / event streams

Configure your ESP to send bounce and complaint events to a secure endpoint in your app.
Your app should:

• Verify the request signature
• Parse the event
• Update your database

3) Apply automatic suppression rules

Typical actions:

Hard bounce

Example: invalid email address, domain doesn’t exist
Action: suppress immediately and never send again

Soft bounce

Example: mailbox full, temporary server issue
Action: retry a limited number of times, then suppress if repeated

Complaint

Example: recipient marked as spam
Action: suppress immediately, often globally across all campaigns

4) Maintain suppression lists

Store recipient state in a table like:

• email
• status = active / bounced / complained / unsubscribed / suppressed
• bounce_count
• last_bounce_reason
• complaint_at
• suppressed_at

Before sending, check this status and skip suppressed recipients.

5) Handle retries carefully

For soft bounces:

• Retry with backoff
• Stop after a threshold, e.g. 3 attempts
• Treat certain “soft” failures as effectively hard if they persist

6) Separate complaints from unsubscribes

A complaint is more serious than an unsubscribe:

• Unsubscribe: remove from mailing list
• Complaint: suppress from all future sends, often immediately

7) Track categories and reasons

Useful fields:

• Bounce type: hard/soft
• SMTP error code
• Diagnostic message
• Complaint source
• Campaign ID / message ID

This helps you identify bad lists, DNS issues, or content problems.

8) Keep compliance in mind

Automatically honoring complaints and bounces helps with:

• CAN-SPAM
• GDPR/consent expectations
• ISP sender reputation
• Deliverability

9) Example workflow

1. Send email
2. ESP posts bounce/complaint event to webhook
3. Your app receives it
4. Validate event signature
5. Mark recipient suppressed
6. Add reason and timestamp
7. Prevent future sends

10) Minimal implementation pattern

If event.type == "bounce" and bounce.severity == "hard":
    suppress(email)

If event.type == "bounce" and bounce.severity == "soft":
    increment_bounce_count(email)
    if bounce_count > 3:
        suppress(email)

If event.type == "complaint":
    suppress(email)

If you want, I can also give you:

• a database schema
• a Node.js/Python webhook example
• or provider-specific steps for SES / SendGrid / Mailgun