Spam Complaints

Spam complaints are individual negative feedback events.

When a recipient clicks “report spam” or “junk,” the mailbox provider treats that as direct evidence that your message was unwanted.

Why they matter

Spam complaints damage sender trust faster than most other metrics. Enough complaints will push future mail into spam, even if your authentication is correct.

Complaints vs complaint rate

A spam complaint is the event itself.

Spam complaint rate is the percentage of delivered emails that turned into complaints.

What usually causes complaints

• Weak targeting
• Recycled or stale lists
• Overly aggressive send frequency
• Unclear opt-out or irrelevant messaging