Definition
A delivery report breaks down what happened to every email in a campaign from the moment it left your sending infrastructure. It categorises each send into one of several outcomes — delivered, hard bounced, soft bounced, blocked, or sent to spam — and provides detailed reasons for non-delivery where available.
Delivery reports are distinct from engagement reports. They measure whether emails reached the inbox, not what recipients did once they arrived. Monitoring delivery reports is essential for maintaining sender reputation and identifying infrastructure or list quality problems before they affect engagement metrics.
Key Delivery Metrics
| Metric | Description | Good Target |
|---|---|---|
| Sent | Total number of emails submitted for sending | N/A |
| Delivered | Emails accepted by the recipient's mail server | 95-99% of sent |
| Hard Bounce | Permanent delivery failure (invalid address) | Under 2% |
| Soft Bounce | Temporary delivery failure (mailbox full, server busy) | Under 5% |
| Blocked | Rejected by recipient's mail server | Under 1% |
| Spam Placement | Emails that landed in spam/promotions folder | Under 5% |
| Deferred | Temporarily queued by recipient server | Varies |
Common Delivery Issues
| Issue | Likely Cause | Solution |
|---|---|---|
| High hard bounce rate | Old or purchased list | Remove invalid addresses, use list hygiene |
| Sudden soft bounce spike | Recipient server issues or IP reputation | Reduce sending volume, warm up IP |
| Increasing spam placement | Sender reputation decline | Review engagement, check blacklists |
| Blocked by specific provider | Complaints or policy violation | Check provider feedback loop, review practices |
| High deferral rate | Sending too fast or too much | Throttle sending, improve list quality |
How to Read a Delivery Report
- Compare delivery rate to baseline: A sudden drop indicates an infrastructure or reputation problem
- Investigate bounce codes: Bounce classification codes (SMTP codes) provide specific reasons for failure
- Check spam placement: Use seed list testing to measure inbox placement rate
- Monitor trends: Track delivery metrics over time to identify gradual reputation decline
- Segment by provider: Gmail, Outlook, Yahoo, and other providers handle delivery differently
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Frequently Asked Questions
Delivery is a binary outcome — an email either was or was not accepted by the recipient's mail server. Deliverability is the broader concept of whether an email reaches the inbox rather than the spam folder. An email can be delivered (accepted by the server) but not have good deliverability (landed in spam).
Review delivery reports after every campaign send. Set up automated alerts for sudden changes in bounce rate, spam complaints, or delivery rate. Weekly trend monitoring helps catch gradual reputation degradation before it becomes critical.
Yes. Email bounces include SMTP status codes that indicate the reason for failure. Common codes include 550 (mailbox not found), 552 (mailbox full), and 450 (temporary failure). Your email platform or delivery report should include these codes for investigation.